Electrochemical hydrogen pumping using a high-temperature polybenzimidazole (PBI) membrane

Electrochemical hydrogen pumping using a high-temperature (>100 °C) polybenzimidazole (PBI) membrane was demonstrated under non-humidified and humidified conditions at ambient pressures. Relatively low voltages were required to operate the pump over a wide range of hydrogen flow rates. The advantages of the high-temperature capability were shown by operating the pump on reformate feed gas mixtures containing various amounts of CO and CO₂. Gas purity measurements on the cathode gas product were conducted and significant reductions in gas impurities were detected. The applicability of the PBI membrane for electrochemical hydrogen pumping and its durability under typical operating conditions were established with tests that lasted for nearly 4000 h.     

ZigBee与ZigBee PRO:哪个功能集最适合?

ZigBee从问世以来不断改进,这种崭新无线标准革新了家庭自动化市场。对于那些对ZigBee不熟悉,或是没机会了解最新规格的人,本文介绍了ZigBee的现状,概略说明ZigBee与ZigBee PRO的功能集,并讨论不同市场与应用环境下的ZigBee,包括ZigBee在医疗市场中的多方面应用。     

嵌入式x86：非PC设计的要旨？

那些考虑把PC构件用于非PC设计的人最好记住：把宝押在PC技术上并非完全正确。在这个体系结构方向经验丰富的同行们已经了解这一点。一方面,人们将受益于PC行业特有的迅猛创新速度,以及全球每年销售的数亿台PC带来的低价格。另一方面,这样的创新速度还导致了迅猛的报废速度,这对于那些生产周期超过六个月的系统而言可能会有问题!     

Design of a Thin Film Infrared Barcode on a Flexible Substrate

We report the design, fabrication and characterization of an infrared barcode. This barcode is composed of a bilayer of titanium and amorphous silicon on a flexible Kapton substrate. Information encoded in the barcode shows high contrast when viewed with an infrared imaging system in the 8 to 12 μm spectral region. The barcode information is concealed under visible viewing conditions, i.e., the barcode appears as an untreated, uniform metal sheet to a detector of visible radiation (400 to 700nm).     

Locating Asian Values in Asian Journalism: A Content Analysis of Web Newspapers

This study tested arguments in the largely anecdotal debate over the existence of Asian values in Asian journalism. News stories uploaded to 10 Asian on-line newspapers were content analyzed for the prevalence of "harmony" and "supportiveness," which the literature suggests as key Asian values. The findings show that the journalistic emphasis on Asian values is concentrated in the Southeast Asia subregion and tracks restrictions on press freedom.     

Time-frequency spectral estimation of multichannel EEG using the Auto-SLEX method

In this paper, we apply a new time-frequency spectral estimation method for multichannel data to epileptiform electroencephalography (EEG). The method is based on the smooth localized complex exponentials (SLEX) functions which are time-frequency localized versions of the Fourier functions and, hence, are ideal for analyzing nonstationary signals whose spectral properties evolve over time. The SLEX functions are simultaneously orthogonal and localized in time and frequency because they are obtained by applying a projection operator rather than a window or taper. In this paper, we present the Auto-SLEX method which is a statistical method that 1) computes the periodogram using the SLEX transform, 2) automatically segments the signal into approximately stationary segments using an objective criterion that is based on log energy, and 3) automatically selects the optimal bandwidth of the spectral smoothing window. The method is applied to the intracranial EEG from a patient with temporal lobe epilepsy. This analysis reveals a reduction in average duration of stationarity in preseizure epochs of data compared to baseline. These changes begin up to hours prior to electrical seizure onset in this patient.     

标准单元ASIC／FPGA的权衡与结构化ASIC

看来您已认定,采取购买并组装现成的专用标准产品(ASSP),如嵌入式控制器、外设芯片等,然后再编写您自己的软件这种做法将不能使您设计的产品与您竞争对手的产品有足够大的差别.因此,您会决定选择芯片级设计.两大硅平台竞争对手及其各自的折衷方案已经在各种工业论坛上引起广泛的争论.不过如果您刚涉足这场争论,则很有必要了解下述有关争论的概要.     

Fuzzy logic control of FES rowing exercise in paraplegia

An indoor personal rowing machine (Concept 2 Inc., Morrisville, VT) has been modified for functional electrical stimulation assisted rowing exercise in paraplegia. To successfully perform the rowing maneuver, the voluntarily controlled upper body movements must be coordinated with the movements of the electrically stimulated paralyzed legs. To achieve such coordination, an automatic controller was developed that employs two levels of hierarchy. A high level finite state controller identifies the state or phase of the rowing motion and activates a low-level state-dedicated fuzzy logic controller (FLC) to deliver the electrical stimulation to the paralyzed leg muscles. A pilot study with participation of two paraplegic volunteers showed that FLC spent less muscle energy, and produced smoother rowing maneuvers than the existing On-Off constant-level stimulation controller.     

Trust for Ubiquitous,Transparent Collaboration

In this paper, trust-based recommendations control the exchange of personal information between handheld computers. Combined with explicit risk analysis, this enables unobtrusive information exchange, while limiting access to confidential information. The same model can be applied to a wide range of mobile computing tasks, such as managing personal address books and electronic diaries, to automatically provide an appropriate level of security. Recommendations add structure to the information, by associating categories with data and with each other, with degrees of trust belief and disbelief. Since categories also in turn confer privileges and restrict actions, they are analogous to rôles in a Rôle-Based Access Control system, while principals represent their trust policies in recommendations. Participants first compute their trust in information, by combining their own trust assumptions with others' policies. Recommendations are thus linked together to compute a considered, local trust assessment. Actions are then moderated by a risk assessment, which weighs up costs and benefits, including the cost of the user's time, before deciding whether to allow or forbid the information exchange, or ask for help. By unifying trust assessments and access control, participants can take calculated risks to automatically yet safely share their personal information.