Peroxide modification of linear low-density polyethylene: A comparison of dialkyl peroxides

A commercial-grade LLDPE resin was cross-linked using three different dialkyl peroxides, at three different concentrations. The peroxides were ranked in order of their Cross-linking efficiency and their effectiveness at increasing the storage modulus of the virgin resin at the cure temperature. The chemical mechanism by which the cross-linking occurs is shown to be closely related to the changes in concentrations of reactive vinyl species on the polyethylene molecules, which follows well with proposed mechanisms of previous publications. Finally, a direct relationship is shown to exist between the rate of peroxide decomposition and the rate of increase in storage modulus of the rubbery modified resin during the curing reaction. © 1993 John Wiley & Sons, Inc.     

Low temperature fuel cells: Interactions between catalysts and engineering design

For many potential applications of fuel cells, especially road transport, it is highly desirable to use liquid fuels. In this paper it is shown that whether direct fuel cell systems (methanol/air) or indirect, hydrogen reformer to hydrogen are chosen, catalyst performance and cost plays a dominant role in the overall design. Notably, the maximum current densities which can usefully be employed are limited by the conductivity of low cost intercell plates in bipolar designs. Thus to attain respectable volume power densities, thin cell stack designs are essential. Considerations of overall simplicity, cooling and water control together with the need to operate at atmospheric pressure because of the cost, noise and inefficiency of air compressors all favour operating at 100°C or below. Although a number of systems could be constructed with known technology, costs are still too high for all but specialised applications. While useful engineering design work can be done using existing catalysts, present costs are far too high to justify widespread application. The recent discovery in the authors' laboratory of a base metal catalyst for the electrolytic oxidation of methanol together with past workers who have presented data on effective non-platinum air cathodes in acid electrolytes suggest that the quest is worthwhile. Bearing in mind the need to reduce total costs, while some system engineering development is worthwhile to provide solutions to the various physical problems involved, the authors argue that the primary effort on fuel cells should be in the fields of catalysis and electrode structure.     

Situations in LTL as strings

Situations serving as worlds as well as events in linguistic semantics are formulated as strings recording observations over discrete time. This formulation is applied to a linear temporal logic, in line with L. Schubert’s distinction between described and characterized situations. The distinction is developed topologically and computationally, and linked to the opposition between truth-conditional and proof-conditional semantics. For a finitary handle on quantification, strings are associated with situations not only on the basis of observation but also through derivation and constraint satisfaction. The constraints specified lead to an implementation simpler than the derivations given.     

使用MATLAB为System Generator for DSP创建IP

使用MATLABM文件借助AccelChip综合工具优化FPGA实现 将基于图形和基于语言的设计方法结合起来最能准确描述DSP系统。DSP建模软件行业专家The MathWorks提供了一种称为Simulink的时序精度的图形化设计环境和一种称为MATLAB的数学建模语言，从而满足了这种二分法。     

Channelization for software defined base-stations

Channelization is the task of channel selection in a communications receiver. Usually it comprises down-conversion of the signal to base-band and channel filtering. To be able to influence the characteristics of channelization by means of software it is advantageous to realize as much as possible of the channelization functionality with digital signal processing. In base-stations several channels have to be received in parallel. An obvious approach to meet this task is to have a separate channelizer for each channel. This so-called per-channel approach does not look very elegant. An alternative is to employ filter banks. This promises to save much effort since the necessary filter is implemented only once for all channels. Both approaches are introduced and discussed in detail. Finally, they are compared with respect to their multiplication rate. The result of this comparison is somewhat surprising.     

A test of the tau-dot hypothesis of braking control in the real world.

A controlled experiment used instrumented vehicles in a real-world driving task to compare D. N. Lee's (1976) tau-dot hypothesis of braking control with an alternative based on the direct estimation and control of ideal deceleration (T. Yates, M. Harris, & P. Rock, 2004). Drivers braked to stop as closely as possible to a visual target from different starting speeds and times-to-contact. The data provided little support for the tau-dot hypothesis, and analysis suggested that braking in the real world is better explained by a direct deceleration strategy. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Expression of lumican in human lungs

With the explosion of genetic information, there has been a recognized need for more genetic knowledge among health care professionals. The National Coalition for Health Professional Education in Genetics (NCHPEG) was established in 1996 to address this need. This article briefly outlines the mission of this Coalition and gives an overview of its relationship to acute and critical care nurses.     

Nonlinear iterative learning control with applications to lithographic machinery

An experimental demonstration is given of (nonlinear) iterative learning control applied to a reticle stage of a lithographic wafer scanner. To limit the presence of noise in the learned forces, a nonlinear amplitude-dependent learning gain is proposed. With this gain, high-amplitude signal contents is separated from low-amplitude noise, the former being compensated by the learning algorithm. Contrary to the underlying linear design, the continuously varying trade-off between high-gain convergence rates and low-gain noise transmission demonstrates a significant improvement of the nonlinear design in achieving performance.     

Improving command and control speech recognition on mobile devices: using predictive user models for language modeling

Command and control (C&C) speech recognition allows users to interact with a system by speaking commands or asking questions restricted to a fixed grammar containing pre-defined phrases. Whereas C&C interaction has been commonplace in telephony and accessibility systems for many years, only recently have mobile devices had the memory and processing capacity to support client-side speech recognition. Given the personal nature of mobile devices, statistical models that can predict commands based in part on past user behavior hold promise for improving C&C recognition accuracy. For example, if a user calls a spouse at the end of every workday, the language model could be adapted to weight the spouse more than other contacts during that time. In this paper, we describe and assess statistical models learned from a large population of users for predicting the next user command of a commercial C&C application. We explain how these models were used for language modeling, and evaluate their performance in terms of task completion. The best performing model achieved a 26% relative reduction in error rate compared to the base system. Finally, we investigate the effects of personalization on performance at different learning rates via online updating of model parameters based on individual user data. Personalization significantly increased relative reduction in error rate by an additional 5%.     

Modeling conversation policies using permissions and obligations

Both conversation specifications and policies are required to facilitate effective agent communication. Specifications provide the order in which speech acts can occur in a meaningful conversation, whereas policies restrict the specifications that can be used in a certain conversation based on the sender, receiver, messages exchanged thus far, content, and other context. We propose that positive/negative permissions and obligations be used to model conversation specifications and policies. We also propose the use of ontologies to categorize speech acts such that high level policies can be defined without going into specifics of the speech acts. This approach is independent of the syntax and semantics of the communication language and can be used for different agent communication languages. Our policy based framework can help in agent communication in three ways: (i) to filter inappropriate messages, (ii) to help an agent to decide which speech act to use next, and (iii) to prevent an agent from sending inappropriate messages. Our work differs from most existing research on communication policies because it is not tightly coupled to any domain information such as the mental states of agents or specific communicative acts. Contributions of this work include: (i) an extensible framework that is applicable to varied domain knowledge and different agent communication languages, and (ii) the declarative representation of conversation specifications and policies in terms of permitted and obligated speech acts.