Effect of temperature on InGaAsP alloy composition

The influence of growth temperature on the composition of InGaAsP films grown by low pressure metalorganic vapor phase epitaxy (MOVPE) is reported for quaternary (Q) alloys having bandgap wavelengths of λ_g = 1.1, 1.3, and 1.5 μn. Films with these different Q-compositions were deposited lattice matched to InP at a growth temperature of 675°C. Subsequent growth experiments were then performed for each Q-composition in which the input gas flow rates were kept the same and only the temperature changed in 25°C decrements down to 600°C. Photoluminescence (PL) and lattice mismatch (LMM) measurements of the resulting films were used to determine the effect of growth temperature on film composition. The PL data indicate a temperature shift in the PL wavelength of −1.8 nm/ °C for the 1.5Q composition, −2.9 nm/°C for 1.3Q, and −4.3 nm/°C for 1.1Q. Negative shifts were also observed in LMM of −80 ppm/°C for 1.5Q, −150 ppm/°C for 1.3Q, and −250 ppm/°C for 1.1Q. The Ga/In and P/As ratios of the Q-filmswere measured by secondary ion mass spectroscopy and correlated with full-wafer maps of the PL wavelength and lattice mismatch to gain insight into the processes responsible for wafer nonuniformity in MOVPE.     

Cigarette smokers do more than just smoke cigarettes.

Hypothesized that 199 17–60 yr old light and moderate-to-heavy (MH) cigarette smokers, compared with 675 nonsmokers, would exhibit significantly less healthy attitudes and behaviors on several dimensions of the risk to coronary heart disease (CHD). A factor analysis of survey items measuring knowledge, attitudes, and behaviors in 5 CHD risk areas produced 4 factors: Attitudes, Health Consciousness, Knowledge, and Unhealthy Behaviors. Smokers vs nonsmokers exhibited less positive attitudes toward CHD risk behaviors, whereas MH smokers, as compared with the light smokers and the nonsmokers, exhibited lower levels of health consciousness and enacted unhealthy behaviors at a greater frequency. Results support the hypothesis that smokers exhibit a less healthy lifestyle as shown by cognitive, behavioral, and motivational dimensions related to cardiovascular health. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A Spoken Dialogue System for Navigation in Non-Immersive Virtual Environments

Navigation is the process by which people control their movement in virtual environments and is a corefunctional requirement for all virtual environment (VE) applications. Users require the ability to move, controllingorientation, direction of movement and speed, in order to achieve a particular goal within a VE. Navigation israrely the end point in itself (which is typically interaction with the visual representations of data) but applicationsoften place a high demand on navigation skills, which in turn means that a high level of support for navigationis required from the application. On desktop systems navigation in non‐immersive systems is usually supportedthrough the usual hardware devices of mouse and keyboard. Previous work by the authors shows that many usersexperience frustration when trying to perform even simple navigation tasks — users complain about getting lost,becoming disorientated and finding the interface `difficult to use'. In this paper we report on work in progressin exploiting natural language processing (NLP) technology to support navigation in non‐immersive virtualenvironments. A multi‐modal system has been developed which supports a range of high‐level (spoken) navigationcommands and indications are that spoken dialogue interaction is an effective alternative to mouse and keyboardinteraction for many tasks. We conclude that multi‐modal interaction, combining technologies such as NLP withmouse and keyboard may offer the most effective interaction with VEs and identify a number of areas where furtherwork is necessary. ACM CSS: I.3.6 Computer Graphics Methodology and Techniques—Interaction and Techniques, I.3.7 Three‐DimensionalGraphics and Realism—Virtual Reality, I.2.7 Natural Language Processing—Speech Recognitionand Synthesis     

氧饱和煤焦和二氧化碳气化煤焦的TPD—MS谱分析

氧饱和煤焦的TPD-MS谱中的CO_2脱附曲线是宽阔带状,在683K附近有一个脱附峰,CO脱附曲线有一个由963K主峰和1083K的肩峰组成的巨大脱附峰及一个在1473K附近的脱附峰。CO_2气化煤焦的TPD—MS谱只有一条CO脱附曲线,在1253和1473K附近突出两个脱附峰。用CO处理的煤焦样品的TPD-MS谱与CO_2气化煤焦样品的TPD-MS谱相似。由此推测仅有两种分别具有半醌型和环醚型结构的碳表面氧化物参与气化反应,并从结构角度解释了煤焦CO_2气化反应的机理。     

Flux and rejection in the ultrafiltration of colloids

Charge on colloidal particles is shown to affect the filtration process in two ways. The effect of changing the charge of the particles, such as by varying pH, is to alter the observable flux which goes through a minimum as the charge is increased. At fixed charge the flux first decreases with particle size and then increases. Charge also influences the mechanism of particle rejection. If primary particles are stable colloids, smaller than the surface pores, they may penetrate the membrane but not necessarily pass all the way through. When particle charge is low enough for flocculation to be significant, rejection will most likely occur at the membrane surface as flocculation results in particles growing to become large enough to be rejected.     

Modifying proteins for maximum utilization in the ruminant

Much of the early work on nitrogen metabolism in ruminants has clearly established that the rumen microflora have a considerable modifying effect on the utilization of dietary nitrogen. This modifying effect may be advantageous to the animal under certain conditions, i.e., when the diet contains mainly poor quality protein or a nonprotein nitrogenous material such as urea. On the other hand, this modifying effect may not be advantageous when high quality protein is fed. From a practical standpoint it appears that limiting the degradation of dietary protein in the rumen would be advantageous under most conditions. Chemical modification of good quality proteins or coating of proteins and individual amino acids to render them resistant to microbial attack, without greatly reducing their nutritive value in the small intestine, appears to offer the most promising approach. Journal Paper No. J-6943 of the Iowa agriculture and Home Economics Experiment Station, Ames, Iowa. Presented at the Porter Williams Symposium on Proteins, AOCS Meeting, Houston, May 1971.     

New risk assessment methodology for coal mine excavated slopes

This paper presents a new risk assessment methodology for coal mine excavated slopes. This new empirical-statistical slope stability assessment methodology(SSAM) is intended for use by geotechnical engineers at both the design review and operational stages of a mine's life to categorise the risk of an excavated coal mine slope. A likelihood of failure is determined using a new slope stability classification system for excavated coal mine slopes developed using a database of 119 intact and failed case studies sourced from open cut coal mines in Australia. Consequence of failure is based on slope height and stand-off distance at the toe of the excavated slope. Results are presented in a new risk matrix, with slope risk being divided into low, medium and high categories. The SSAM is put forward as a new risk assessment methodology to assess the potential for, and consequence of, excavated coal mine slope failure.Unlike existing classification systems, assumptions about the likely failure mode or mechanism are not required. Instead, the SSAM applies an approach which compares the conditions present within the excavated slope face, with the known past performance of slopes with similar geotechnical and geometrical conditions, to estimate the slope's propensity for failure. The SSAM is novel in that it considers the depositional history of strata in an excavated slope and how this sequence affects slope stability. It is further novel in that it does not require explicit measurements of intact rock, rock mass and/or defect strength to rapidly calculate a slope's likelihood of failure and overall risk. Ratings can be determined entirely from visual observations of the excavated slope face. The new SSAM is designed to be used in conjunction with existing slope stability assessment tools.