Correlation methods

The paper discusses the theory of correlation methods, emphasising the use of crosscorrelation to determine weighting functions of linear systems. The corresponding frequency domain expressions are derived. Correlation methods have been applied widely in engineering and several applications, and the problems associated with them, are discussed.     

Influence of Sampling and Comparison Processes on the Development of Communication Effectiveness.

Children's communication performance improves with age, which could result from increases in children's vocabularies, changes in their strategies of selecting messages from their vocabularies, or both. Three experiments were conducted to evaluate these explanations. Two types of communication tasks were employed. One task required that speakers have adequate vocabulary, while the other task had the additional requirement that speakers select their messages based on comparison activity. Results indicated that second-, fourth-, and sixth-grade children were equally effective communicators on the former task and that younger children were poorer communicators on the latter task. These data suggest that younger children have inadequate comparison strategies. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Exercise-induced asthma--clinical, physiological, and therapeutic implications

Exercise provokes acute airways obstruction, maximum shortly after stopping, in virtually all asthmatic patients. The severity of this exercise-induced asthma (EIA) depends upon the type of exercise, with running being the most asthmogenic, swimming and walking the least, and cycling intermediate even with the same metabolic stress. The duration and severity of the exercise also affect the amount of EIA, the maximum amount of being obtained after 6 to 8 min of running hard enough to raise the heart rate to 180 beats per minute (bpm) in children or 140 bpm in adults. EIA is not the result of hyperventilation or blood gas changes and appears to depend on the release of relatively short-lived transmitter agents during the exercise period. EIA can be prevented by premedication with bronchodilators, especially with sympathomimetics. Cromolyn sodium is not a bronchodilator but inhibits EIA in most subjects if given before the exercise. EIA can also be inhibited by atropine and alpha adrenergic blockers in some patients, but by steroids in only a minority of cases. Exercise testing provides a good model for study of the physiology and pharmacology of clinical asthma, and is some guide to prognosis, but it must be properly standardized and the important differences must be appreciated.     

New class of pseudorandom ternary sequences

The crosscorrelation function between certain pairs of binary maximum-length sequences of the same period has only three levels. The method of formation of a class of these ternary crosscorrelation sequences is described, and some of the properties of the class are listed.     

High power, diffraction-limited emission from monolithically integrated active grating master oscillator power amplifier (lasers)

A novel monolithically integrated master oscillator power amplifier with a distributed amplifier/grating output coupler is demonstrated which emits 370 mW in a single-frequency diffraction-limited beam without any form of active phase control. The distributed amplifier/grating output coupler results in a guided mode power that saturates along the direction of propagation, providing a uniform carrier density to preserve the flatness of the radiated phase front.<>     

丹尼尔斯大厦 加拿大多伦多

正多伦多大学丹尼尔斯建筑、景观和设计学院的设计采用了分期的方法,包括修复和扩建以前称为"知识学院"的标志性建筑,将现有建筑物改造成与教学和需求更相关的框架体系。这个十九世纪遗址的总体规划是通过对预期用途模式和场地生态的分析而制定的,目的是重新定位校园西南角与安大略湖的轴线,并为学院创造新的特性。丹尼尔斯建筑、景观和设计学院需要一个可持续发展的新型工     

Biocatalytic electrode improvement strategies in microbial fuel cell systems

Microbial fuel cells (MFCs) produce electricity as a result of the microbial metabolism of organic substrates, hence they represent a sustainable approach for energy production and waste treatment. If the technology is to be implemented in industry, low cost and sustainable bioelectrodes must be developed to increase power output, increase waste treatment capacity, and improve service intervals. Although the current application of abiotic electrode catalysts, such as platinum and electrode binders such as Nafion leads to greater MFC performance, their use is cost prohibitive. Novel bioelectrodes which use cost effective and sustainable materials are being developed. These electrodes are developed with the intention to reduce start-up time, reduce costs, extend life-span and improve core MFC performance metrics (i.e. power density, current density, chemical oxygen demand (COD) reduction and Coulombic efficiency (CE)). Comparison of different MFC systems is not an easy task. This is due to variations in MFC design, construction, operation, and different inocula (in the case of mixed-culture MFCs). This high intra-system variability should be considered when assessing MFC data, operation and performance. This review article examines the major issues surrounding bioanode and biocathode improvement in different MFC systems, with the ultimate goal of streamlining and standardising improvement processes. © 2018 Society of Chemical Industry     

Materials analysis with a position-sensitive atom probe

A position-sensitive detector has been combined with time-of-flight mass spectrometry in the atom probe field-ion microscope to yield a system in which both chemical identity and spatial information are obtained for individual ions field-evaporated from the specimen surface. This allows the variations in composition originally present in the sample to be reconstructed in 3-D with sub-nanometre resolution. The prototype position-sensitive atom probe is being used to study phase chemistry in a number of metallurgical alloys, including accurate composition determination of 1–2 nm Cu-rich precipitates formed in Fe–1.3% Cu–1.4%Ni aged to peak hardness. Other applications of the position-sensitive atom probe (POSAP) include the analysis of surface layers on superconductors and atom probe studies of semiconductor multiple quantum wells. These initial applications of the instrument are reported, and the limitations and intended improvements to the instrument are discussed.