2003年采购指南

现在名牌笔记本电脑也卖到1000美元以下了,你也该想想你的下一台PC是否应该是笔记本     

A Neuro-fuzzy Coding for Processing Incomplete Data: Application to the Classification of Seismic Events

This letter presents a method for modelling and processing incomplete data in connectionist systems. The approach consists in applying a neuro-fuzzy coding to the input data of a neural network. After an introduction to the different kinds of imperfections, we propose a neuro-fuzzy coding in order to take incomplete data into account. We show the efficiency of this coding on the problem of the classification of seismic events. The results show that a neuro-fuzzy coding of the inputs of a neural network increases the performance and classifies incomplete data with little affect on the results.     

Using network hacking techniques to disrupt military operational networks

It starts in a small way. An Internet-originated electronic mail message received by various technical ratings and Combat Information Center (CIC) officers on a ship deployed in a very high threat area of the Persian Gulf relays news of a natural disaster involving their families that supposedly occurred during a cookout:     

Personal security

I am sitting on a plane, listening to two executives outline their strategy for a major buyout of a bridge/router vendor. Since I am a geek and understand what they are talking about, it's an interesting set of tactics that they are considering to get the price of the company down to something they want. What's even more interesting is how open they are with what they are talking about and, even more, I know the president of the company which they are planning to acquire. It would be very easy for me to make a phone call when we land and completely trash all their plans.     

Reduction of Friction by Functionalised Viscosity Index Improvers

A range of functionalised polymethacrylate copolymers have been synthesised with different functionalities, polymer architecture and molecular weight. It is shown that appropriately functionalised block copolymers give enhanced film thickness and greatly reduced friction under low entrainment speed conditions, even with polymer concentration as low as 1% wt. This behaviour almost certainly results from the formation of an adsorbed brush-like film of thickness ca 20 nm on each polar surface. These films provide a highly viscous inlet that promotes fluid entrainment and thus maintains a separating film down to very low entrainment speed. The adsorbed polymer films are also able to maintain separation in stationary contact conditions. Randomly distributed copolymers do not show this type of behaviour. The friction reduction observed is more effective in unidirectional, mixed sliding–rolling than in reciprocating, sliding conditions. However, it is found that functionalised polymers and conventional organic and molybdenum-based friction modifiers can be combined to provide effective friction reduction over the whole range of rubbing conditions.     

Mapping of polished coal surfaces by automated reflectance microscopy

The capabilities of Rapid Scan, a system of automated reflectance microscopy, has been extended to the actual mapping of petrographic variation across polished coal surfaces. This is accomplished through computer control of a microscope stepping stage and the storage of binary reflectance data on disc in a matrix form which permits the proper spatial arrangement of values to be re-created. The maps depict lithotype variation, and the distribution of mineral occurrences, cracks and cleat. An image processor can be employed in further map analysis such as the compilation of reflectance profiles from selected areas.     

Syllabic priming in lexical decision and naming tasks: The syllable congruency effect re-examined in French.

This study investigated the role of the syllable in visual recognition of French words. The syllable congruency procedure was combined with masked priming in the lexical-decision task (Experiments 1 and 3) and the naming task (Experiment 2). Target words were preceded by a nonword prime sharing the first three letters that either corresponded to the syllable (congruent condition), or not (incongruent condition). When primes were displayed for 67 ms, similar results were found in both the lexical decision and the naming tasks. Consonant-vowel targets such as BA.LANCE were recognised more rapidly in the congruent condition than in the incongruent and control conditions, while consonant-vowel-consonant targets such as BAL.CON were recognised more rapidly in the congruent and incongruent conditions than in the control condition. When a 43-ms SOA was used in the lexical-decision task, no significant priming effect was obtained. The results are discussed in an interactive-activation model incorporating syllable units. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Tailoring Materials for Mottronics: Excess Oxygen Doping of a Prototypical Mott Insulator

The Mott transistor is a paradigm for a new class of electronic devices—often referred to by the term Mottronics—which are based on charge correlations between the electrons. Since correlation‐induced insulating phases of most oxide compounds are usually very robust, new methods have to be developed to push such materials right to the boundary to the metallic phase in order to enable the metal–insulator transition to be switched by electric gating. Here, it is demonstrated that thin films of the prototypical Mott insulator LaTiO₃ grown by pulsed laser deposition under oxygen atmosphere are readily tuned by excess oxygen doping across the line of the band‐filling controlled Mott transition in the electronic phase diagram. The detected insulator to metal transition is characterized by a strong change in resistivity of several orders of magnitude. The use of suitable substrates and capping layers to inhibit oxygen diffusion facilitates full control of the oxygen content and renders the films stable against exposure to ambient conditions. These achievements represent a significant advancement in control and tuning of the electronic properties of LaTiO_3+x thin films making it a promising channel material in future Mottronic devices.     

Characterization of multilayer anti-fog coatings

Fog formation on transparent substrates constitutes a major challenge in several optical applications requiring excellent light transmission characteristics. Anti-fog coatings are hydrophilic, enabling water to spread uniformly on the surface rather than form dispersed droplets. Despite the development of several anti-fog coating strategies, the long-term stability, adherence to the underlying substrate, and resistance to cleaning procedures are not yet optimal. We report on a polymer-based anti-fog coating covalently grafted onto glass surfaces by means of a multistep process. Glass substrates were first activated by plasma functionalization to provide amino groups on the surface, resulting in the subsequent covalent bonding of the polymeric layers. The anti-fog coating was then created by the successive spin coating of (poly(ethylene-maleic anhydride) (PEMA) and poly(vinyl alcohol) (PVA) layers. PEMA acted as an interface by covalently reacting with both the glass surface amino functionalities and the PVA hydroxyl groups, while PVA added the necessary surface hydrophilicity to provide anti-fog properties. Each step of the procedure was monitored by XPS, which confirmed the successful grafting of the coating. Coating thickness was evaluated by profilometry, nanoindentation, and UV visible light transmission. The hydrophilic nature of the anti-fog coating was assessed by water contact angle (CA), and its anti-fog efficiency was determined visually and tested quantitatively for the first time using an ASTM standard protocol. Results show that the PEMA/PVA coating not only delayed the initial period required for fog formation but also decreased the rate of light transmission decay. Finally, following a 24 hour immersion in water, these PEMA/PVA coatings remained stable and preserved their anti-fog properties.     

Weakening the tight coupling between geometry and simulation in isogeometric analysis: From sub‐ and super‐geometric analysis to Geometry‐Independent Field approximaTion (GIFT)

This paper presents an approach to generalize the concept of isogeometric analysis by allowing different spaces for the parameterization of the computational domain and for the approximation of the solution field. The method inherits the main advantage of isogeometric analysis, ie, preserves the original exact computer‐aided design geometry (for example, given by nonuniform rational B‐splines), but allows pairing it with an approximation space, which is more suitable/flexible for analysis, for example, T‐splines, LR‐splines, (truncated) hierarchical B‐splines, and PHT‐splines. This generalization offers the advantage of adaptive local refinement without the need to reparameterize the domain, and therefore without weakening the link with the computer‐aided design model. We demonstrate the use of the method with different choices of geometry and field spaces and show that, despite the failure of the standard patch test, the optimum convergence rate is achieved for nonnested spaces.