Femtocell技术的由来、优势和市场前景

Femtocell是用于增强室内无线覆盖的一项新技术,近年来受到了业界的广泛注意,发展十分迅速。本文叙述了Femtocell技术的由来和发展;讨论了Femtocell系统的优越性和需解决的关键技术;介绍了国外业界对Femtocell市场的预测。     

Evaluation of Multipoint Dosing Strategy in a Miniaturized Tubular Reactor: Nitration of Salicylic Acid

A 2D non‐isothermal reaction engineering model for a tubular reactor was developed for a complex reaction network of salicylic acid nitration. The influence of different operating and design parameters was studied to minimize the amount of secondary nitration products and limit the maximum temperature inside the reactor. Critical temperature effects were observed for larger reaction tubes, whereas close to isothermal conditions were perceived in smaller tubes. With single‐point dosing of both reactants, complete conversion can be achieved but formation of secondary nitration products cannot be avoided. For a given number of dosing points, a suitable combination of the operating parameters allowed to achieve complete conversion and better yield of the desired product.     

Continuous production of biodiesel with supercritical methanol: Optimization of a scale-up plug flow reactor by response surface methodology

A scale-up plug flow reactor was evaluated for the continuous production of biodiesel from refined palm kernel oil (PKO) with supercritical methanol and optimized by response surface methodology. The effects of the operating temperature (270–350 °C), pressure (15.0–20.0 MPa) and methanol:PKO molar ratio (20:1–42:1) were evaluated at a constant residence time of 20 ± 2 min by using a central composite design. Analysis of variance demonstrated that a modified quadratic regression model gave the best coefficient of determination (R² = 0.9615) and adjusted coefficient of determination (Adj. R² = 0.9273). The interaction terms in the regression model illustrated small synergistic effects of both temperature–pressure and temperature–methanol:PKO molar ratio. The optimal conditions were 325 ± 5 °C, 18.0 ± 0.5 MPa and a methanol:PKO molar ratio of 42 ± 2:1, attaining a maximum production rate of 18.0 ± 1.5 g biodiesel/min with a fatty acid methyl ester content of 93.7 ± 2.1%. The product obtained from the optimal conditions had high cetane number, and could be considered as a fuel additive for cetane number enhancement.     

轻烃回收装置工艺设备、管线腐蚀堵塞原因分析

轻烃回收装置原料中含HCl,H2 S和NH3等腐蚀性介质 ,对工艺设备和管线产生了较严重的腐蚀 ,致使设备和管壁壁厚减薄、管线堵塞、1Cr18Ni9Ti不锈钢法兰开裂。经改进“一脱二注”方案 ,不注入氨水 ,而注入不形成垢的有机胺 ,并辅以其他措施 ,收到了较好的效果     

基于USB的多路输入输出模块设计

USB总线是一种新型的串行总线，即插即用、可热插拔、最多同时可连接127个设备，尤其是USB2．0规范的提出，使得传输速率最高可以达到480Mbps且具有向下兼容的特征。通过对USB2．0规范的研究，结合实际工作介绍了基于USB总线的多路输入输出模块设计。利用CYPRESS公司的USB2．0控制芯片EZ-USB FX2实现了USB接口电路设计，并解决了多个FPGA之间的通信问题。     

移动互连技术研究

无线通讯的发展 ,让网络通讯随之移动起来。人们在移动的环境中希望能够享受到方便的移动服务。传统的网络协议已不能完全满足这个需要。移动互连技术 ,即移动IP技术的出现 ,填补了这一空白。介绍和分析了移动互连技术的工作原理 ,并讨论IPv6为该技术提供的支持 ,最后总结了移动互连技术有待解决的几个问题     

Intelligent System for Adapting to a User’s Characteristics

In this paper, we propose an intelligent system that adapts itself to a user’s characteristics or habits. The proposed intelligent system is composed of two Learning Vector Quantisation (LVQ) networks, commonly used in the fields of pattern recognition and signal processing. From the external condition of the plant, the first LVQ network learns to recognise the pattern of the sensed signal, and then aids the second LVQ to learn the user’s characteristics or habits so as to automatically produce the user’s favoured output. To verify the usefulness of the proposed method, we simulated and experimented with a variable illuminator. Both simulation and experimental results showed that the proposed intelligent system learns to automatically produce the illuminator output that the user most favours for the circumstances.     

Development and evaluation of an affordable lift device to reduce musculo-skeletal injuries among home support workers

Home support workers (HSWs) work in clients' homes assisting with rehabilitation and activities of daily living. Like all health-care professionals, HSWs are at an increased risk for developing back injuries. Lift devices have been shown to reduce injuries to the worker. Presently, there are few lifting devices for home use that cost under $4000 CDN. Our study involved designing a safe and affordable lift device (retail cost under $2000 CDN) to be used by HSWs in the home and evaluating it in a typical bathroom. Thirty-eight HSWs and three seniors evaluated the BCIT lift, a commercially available lift (BHM Medical Inc.) and the manual method of transfer and lift. Results indicated that the BCIT lift was an improvement over the manual method of transferring, and approximated the more expensive, automatic lift in terms of perceived exertion, ease of use and safety. Feedback provided to the researchers has been incorporated into a new, ergonomically sound and marketable lift device.     

Investigating design issues in household environments

This paper argues that the current involvement of end users in the design of technological artefacts is too superficial. It is common to involve people in requirements generation, but rarely in product inception or design. A study is reported involving five households in central Scotland, who were each visited on three occasions, using a new investigative framework. Illustrative examples are provided of the strengths and weaknesses of the methods used. Despite the latter, it is demonstrated that the general public can both generate and critique design ideas and that valuable contributions to understanding people's relationships with technologies can be expected both from children and from the elderly. Electronic Publication     

The future of the personal computer in the home: A research note

It is widely accepted that, if technology is to be more accepted in the home, it must change to better suit this environment. A number of researchers have argued that this change will take the form of the post-PC world. Rather than use home PCs, it is predicted we will use single-function appliances, crafted for specific purposes. As currently stated, the model is flawed. It over-emphasises usability barriers to home PC adoption, and ignores the great success of multi-function devices. More seriously, the argument is based on a model of innovative technologies competing with and then superseding existing technologies. This is a simplification-often there is a process ofbalkanisation, where the market and use of devices changes, grows, shrinks and is subdivided. One potential balkanisation of the home PC market space is discussed, producing a range of PC-type devices which better fit home environments.