离子自拆分法合成D-(一)-对羟基苯甘氨酸

研究了用离子自拆分方法拆分外消旋对羟基苯甘氨酸(DL-HPG)而合成D-(—)-对羟基苯甘氨酸(D-HPG)。采用正交试验确定了最佳反应条件:在丙酮和水的混合溶剂中,等物质的量的DL-HPG和硫酸在60℃下加入D-HPG,搅拌反应15min左右,降温过滤得到D-HPG的硫酸盐,水解即可得到D-HPG(光学纯度99％),一次性总收率达到20％。适于工业生产。     

Manipulating the phase morphology in PPS/PA66 blends using clay

By adding a small amount of clay into poly(p‐phenylene sulfide) (PPS)/polyamide 66 blends, the morphology was found to change gradually from sea–island into cocontinuity and lamellar supramolecular structure, as increasing of clay content. Clay was selectively located in the PA66 phase, and the exfoliated clay layers formed an edge‐contacted network. The change of morphology is not caused by the change of volume ratio and viscosity ratio but can be well explained by the dynamic interplay of phase separation between PPS and PA66 through preferential adsorption of PA66 onto the clay layers and through layer–layer repulsion. This provides a means of manipulating the phase morphology for the immiscible polymer blends. The mechanical and tribological properties of PPS/PA66 blends with different phase morphologies (different clay contents) were studied. Both tensile and impact strength of the blends were found obviously increased by the addition of clay. The antiwear property was greatly improved for the blends with cocontinuous phase form. Our work indicates that the phase‐separating behavior of polymer blends contained interacting clay can be exploited to create a rich diversity of new structures and useful nanocomposites. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Anisotropic geodesics for live‐wire mesh segmentation

We present an interactive method for mesh segmentation that is inspired by the classical live‐wire interaction for image segmentation. The core contribution of the work is the definition and computation of wires on surfaces that are likely to lie at segment boundaries. We define wires as geodesics in a new tensor‐based anisotropic metric, which improves upon previous metrics in stability and feature‐awareness. We further introduce a simple but effective mesh embedding approach that allows geodesic paths in an anisotropic path to be computed efficiently using existing algorithms designed for Euclidean geodesics. Our tool is particularly suited for delineating segmentation boundaries that are aligned with features or curvature directions, and we demonstrate its use in creating artist‐guided segmentations.     

高纯聚氯化铝的制备及研究进展

近年来,随着现代水处理技术的迅速发展,高纯聚氯化铝作为一种优良的无机混凝剂受到了广泛关注。常规的聚氯化铝生产方法中,产品中的铁及其他重金属离子含量较高。因此,杂质含量的控制对生产高纯聚氯化铝尤为重要。归纳总结了5种主要的高纯聚氯化铝制备方法（直接合成法、净化法、电解法、凝胶法及热解活化法等）的研究进展及优缺点,指出了高纯聚氯化铝制备过程中存在的问题,最后展望了高纯聚氯化铝的发展趋势。     

Content-aware optimization on rate-distortion and network traffic for scalable video multicast networks

This paper aims to optimize the content-aware prioritization of scalable video multicast, which is coupled with multipath streaming and network coding based routing. It constructs multiple layer distribution meshes for the scalable video stream to minimize the total video distortion at all the receivers, determines the base layer meshes with minimum costs to maintain application-layer QoS and the layer synchronization of SVC streaming, and improves the network throughput by encouraging path-overlapping transmissions and thus allowing bandwidth sharing among different receivers for the same video layer by utilizing network coding. The targeted problem is formulated into a minimization programming in which the quality variation between layers, the transmission cost of the base layer, as well as the efficient resource utilization are jointly considered. By decomposition and dual approach, the global convex problem is solved by a two-level decentralized iterative algorithm. The implementation of the distributed algorithm is discussed with regard to the communication overhead, and the convergence performance is validated by numerical experiments. Packet-level simulations demonstrate that the proposed algorithm could approximately achieve the maximum flow rates determined by Max-Flow Min-Cut Theorem and benefit the overall received video quality.     

Applying “Design Thinking” in the context of media management education

“Design Thinking” – a cross-disciplinary and user centered method – is an approach towards the discovery of solutions and sparks innovative thinking in many ways. It also can be argued, that designers put themselves in the place of the user rather than co-creating with the consumer. Innovation is one of the current keywords across many industries, and many attempt to find new solutions to daily problems. Design Thinking as method allows to understand user needs and understand their principle problems in daily life. The design process uses intensive collaboration in cross-disciplinary settings and is divided into the exploration of the problem space and the solution space to achieve new ways of solving existing problems. Design Thinking has to integrate into the innovation process and into organizational structures right from the beginning. It constitutes a complement to classical analytical processes for problems that require lateral, not linear thinking. This article reviews the practical application of this energetic methodology in the academic context and presents some hands-on examples. The course series has been established by the Entertainment and Media Management Lab. (EMMi Lab.) at the Tampere University of Technology (TUT) and was held in cooperation with students from the University of Tampere (UTA), and the Tampere University of Applied Sciences (TAMK). One course has been held in cooperation with the University of Applied Sciences Magdeburg-Stendal, Germany. This article describes how to train students especially with strong technical background and analytical mind-sets in the development of innovations in the field of media, foster creative thinking, and achieve problem solutions beyond the current state of the art. We present the basic curriculum, course structure, goals & objectives, applied methods, settings, and theoretical aspects of Design Thinking. Our experience and reflections on conducting the courses concludes this article. The article shall be an introductory guide for anyone who intends to organize a similar course in the university context.     

农配网变压器烧毁的原因分析及防范对策

针对山区阳春市农配网的特点,从线路短路、雷击、负荷不平衡、运行维护不当等四个方面出发,详细分析了可能导致农配网变压器烧毁的原因,并提出了具体的防范对策,为农配网的运行维护人员提供参考,防止事故的发生。     

含有腐植酸的吸水性树脂在溶液及土壤环境中的性质研究

考察了含有腐植酸的吸水性树脂(HA-MA-AM)在溶液以及土壤环境中的性质。当腐植酸钾用量低于40wt%时,在环境pH值为6～7的条件下,HA-MA-AM的吸水倍率明显高于未添加腐植酸钾的MA-AM型保水剂。实验结果表明,HA-MA-AM具有较好保持水分、抑制水分蒸发的作用。     

Synthesis,characterization, and optoelectronic properties of two new polyfluorenes/poly(p‐phenylenevinylene)s copolymers

Two novel copolymers of polyfluorenes/poly(p‐phenylenevinylene)s copolymers with p‐tert‐butyl‐phenylenemethylene groups in the C‐9 position of alternating fluorene unit, poly[1,4‐(2,5‐dibutyloxyl)‐phenyleneviny lene‐alt‐9‐(p‐tert‐butyl‐phenylenemethylene)fluorene] and poly[1,4‐(2,5‐dioctyloxyl)‐phenylenevinylene‐alt‐9‐(p‐tert‐butyl‐phenylenemethylene)fluorine], have been synthesized via the Heck polycondensation reaction. The synthesized polymers were characterized by FTIR, NMR, DSC, TGA, UV–vis, and PL spectra. The polymers showed high glass transition temperatures and good thermal stability. A polymer light‐emitting diode with the configuration ITO/PEDOT:PSS/P2/Ca/Al has been fabricated. The device emitted a yellow light with a peak wavelength of 578 nm similar to the PL spectra of the copolymer film. A maximal luminance of 534 cd/m² was obtained at a driving voltage of 24.5 V. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 3955–3962, 2006     

基于AJAX技术创建的异步方法应用研究

遵循AJAX技术的基本原理,创建了一个简单的异步引用方法,并给出登录实例来说明如何实现该方法的引用,减少代码冗余。主要阐述了通过创建方法,并引用方法到不同Web应用程序中,实现了代码的优化。