Wet and dry tribological behaviors of circular islandic protrusion patterns on M2 steel discs under spinning condition

Under spinning conditions, lubricant on islandic spot patterned M2 steel disc experiences centrifugal and tangential force components. Depending upon the relative position of the spots and the flow of lubricant, accumulation of lubricant in front of patterned islandic spots creates thrusting to mating part and subsequently reduces contact between the mating couple. Whilst wear debris is likely to be spun off the plateau of the spots to their neighbouring valleys so as to reduce wear. Hence, it gives favorable tribological characteristics. Aiming at verifying such mechanisms, studies were performed on M2 steel disc specimens slid with ASSAB 17 tool steel pin. The M2 steel disc specimens were respectively （i） machined with non-patterned （NP）, （ii） etched to produce in-lined （INE） islandic patterns, and （iii） etched to produce staggered （STE） islandic spot patterns. Results indicated that the INE patterned discs gave most favorable wear characteristics, the NP of the worse characteristics whilst the STE ranged in the middle. However, the actual contact mechanism leads to the descending sequence of favorable friction behaviors nominally as： NP, INE and STE.     

Dynamic stair walking of biped humanoid robots

Biped humanoid robots are expected to move around human-centered setting that includes stairs as a major terrain. Reportedly, however, only few of them can walk up and down stairways as of now. Making it worse, even the successful ones carry out such motions either barely in terms of speed or fast enough but in an undisclosed technical manner. In this context, a dynamic gait pattern is proposed anew suitable for stair walks along with a transient pattern and verified by means of a multi-body dynamics analysis software.     

Indexing chromatic and achromatic patterns for content-based colour image retrieval

In this paper, we present a method to represent achromatic and chromatic image signals independently for content-based image indexing and retrieval for image database applications. Starting from an opponent colour representation, human colour vision theories and modern digital signal processing technologies are applied to develop a compact and computationally efficient visual appearance model for coloured image patterns. We use the model to compute the statistics of achromatic and chromatic spatial patterns of colour images for indexing and content-based retrieval. Two types of colour images databases, one colour texture database and another photography colour image database are used to evaluate the performance of the developed method in content-based image indexing and retrieval. Experimental results are presented to show that the new method is superior or competitive to state-of-the-art content-based image indexing and retrieval techniques.     

Social "facilitation" as challenge and threat.

The authors conducted an experiment to test a theoretical explanation of social facilitation based on the biopsychosocial model of challenge and threat. Participants mastered 1 of 2 tasks and subsequently performed either the mastered (i.e., well-learned) or the unlearned task either alone or with an audience while cardiovascular responses were recorded. Cardiovascular responses of participants performing a well-learned task in the presence of others fit the challenge pattern (i.e., increased cardiac response and decreased vascular resistance), whereas cardiovascular responses of participants performing an unlearned task in the presence of others fit the threat pattern (i.e., increased cardiac response and increased vascular resistance), confirming the authors' hypotheses and the applicability of the biopsychosocial model of challenge and threat to explain these results. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

传统图案元素在视觉传达设计中的应用

目的 探索传统图案元素在视觉传达设计中的应用策略.方法 传统图案历经了几千年的传承与发展,其中的精髓是值得肯定的.以此为源头,分析其中的类别与内涵,并尝试将这些经典元素引入当前的视觉传达设计领域.总结了其给予视觉传达设计的文化、社会和经济等方面的重要价值与意义,然后结合传统吉祥元素、传统绘画元素和传统剪纸元素等代表性图案精髓,对各自在视觉传达设计领域的具体应用方式方法进行论述,思考这些传统图案元素在装饰、移植和创新等方面所赋予的视觉传达的方向与路径指引.结论 传统图案是我国自古流传下来的代表性艺术形式之一,有着很强的应用价值与效用,其与视觉传达设计的结合是自身传承方式的创新,是视觉传达设计的尝试,也是社会效益和经济效益的有效实现载体,能够促进视觉传达设计的优化发展,发扬传统文化,促进媒介信息传播途径的拓展.     

Site-Specific Synthesis of Silica Nanostructures on DNA Origami Templates

DNA origami has been widely investigated as a template for the organization of various functional elements, leading to potential applications in many fields such as biosensing, nanoelectronics, and nanophotonics. However, the synthesis of inorganic nonmetallic nanomaterials with predesigned patterns using DNA origami templates has seldom been explored. Here, a novel method is reported to site-specifically synthesize silica nanostructures with designed patterns on DNA origami templates. The molecular dynamic simulation confirms that the positively charged silica precursors have a stronger electrostatic affinity to protruding double-stranded DNA (dsDNA) than DNA origami surfaces. The work describes a novel strategy to fabricate silica nanostructures with nanoscale precision. Moreover, the site-specific silicification of DNA nanoarchitectures expands the scope of customized synthesis of inorganic nonmetallic nanomaterials.     

Precision Imprinted Nanostructural Wood

Wood is a ubiquitous material, widely used in human society, that features naturally abundant, aligned longitudinal cells (e.g., tracheids in softwood and fibers/vessels in hardwood) with diameters of ≈50–1000 µm. Here, the realization of, fine patterns on a wood surface ranging in size from 40 nm to 50 µm by precision imprinting is described. The precision imprinting is enabled by releasing cellulose fibril aggregates from the bondage of lignin through the delignification process, then imprinting in wet condition and fixing the designed configuration in the dry state. Various precision structures on a wood surface using imprinting technology, including dot arrays, lines, triangular features, and other complex patterns, are successfully demonstrated. Even multiscale structures with nanosized lines on the surface of micrometer hemiballs can be acquired. As a proof of concept, the use of surface‐imprinted wood as a microlens array (MLA), which exhibits superior imaging ability and thermal stability even at a high temperature up to 150 °C compared with traditional polystyrene MLA, is demonstrated. This precision imprinted wood may open new possibilities toward environmentally friendly devices and applications in optics, biology, electronics, etc.     

Context-Based Constraints in Security: Motivations and First Approach

Recent research in security shows a real need for contextual information in building highly adaptive security systems. The need for such security for web services is fast becoming imperative. In this paper, we review the main contributions in this domain. Based, on this study we present a glimpse at the CoDiS project; a generic layer for the rapid prototyping of context-based security systems, aiming at getting around the limitations of existing systems.     

基于数据挖掘的促销决策支持系统

提出一种根据客户资料和购物历史数据进行数据挖掘的促销决策支持系统，该系统有机地结合RFM模型、关联规则和序列模式的数据挖掘技术，寻找企业最有价值的目标客户群，发掘目标客户群的商品购买模式，预测目标客户群的商品购买趋势，挖掘目标客户群的购买力，为企业提供动态、实时和准确的促镥决策支持．使企业能对目标客户群采取有针对性的高效的促销措施，以更快的速度、更高的准确度和更出色的客户服务，满足客户个性化的需求，以提高企业的客户服务水平，建立并保持客户忠诚度，增加企业的销售额，降低企业的营销成本．实践证明，该系统高效且可广泛使用．     

R-Tiles

The square root of the Golden Section, , is at times not given its due in discussions regarding the Golden Section. This is an unfortunate situation because its geometric properties provide us with a unique and rarely applied design tool. In this column, geometer Mark Reynolds focuses on the rectangle and its abilities to create an exciting tiling, R-Tiles.