变压吸附富氧工艺用于合成氨制气过程的技术经济分析

本文介绍了变压吸附法制备富氧空气用于合成氨造气系统的新工艺，并对５００００ｔ／ａ合成氨厂进行了技术经济评估。结果表明，同间歇法气化相比，该技术工艺先进且具有显著的经济效益。     

Multidimensional ARKN methods for general oscillatory second-order initial value problems

Based on B-series theory, the order conditions of the multidimensional ARKN methods are presented for the general multi-frequency and multidimensional oscillatory second-order initial value problems by Wu et al. (2009). These multidimensional ARKN methods exactly integrate the multi-frequency and multidimensional unperturbed oscillators. In this paper, we pay attention to the analysis of the concrete multidimensional ARKN methods for the general multi-frequency oscillatory second-order initial value problems whose right-hand side functions depend on both  y$y$and  y^′$y^{\prime }$ (the class of physical problems which fall within its scope is broader). Numerical experiments are carried out to show that the new multidimensional ARKN methods are more efficient compared with some well-known methods for dealing with the oscillatory problems in the scientific literature.     

Muscular fatigue and maximum endurance time assessment for male and female industrial workers

A single arm pushing experiment was conducted in an electronic factory in Yantai, China to assess muscular fatigue using the theoretical models of muscular strength and maximum endurance time (MET) developed by Ma et al. (2009). Seventy seven workers, including 38 males and 39 females, participated in the study. The muscular strength of pushing was measured after the subject pushed a stick, with a force of 2.5 kgf, for 0.5, 1.0, 1.5, 2.0, 2.5, and 3.0 min. Fatigue rate was determined based on a regression approach. In addition to the theoretical model, the MET for such a pushing task was also determined using four empirical models in the literature. The results indicated that females were more resistant to muscular fatigue than males in the pushing task. The results of the muscular strength prediction show that the predictability of the muscular strength model is acceptable. The prediction errors for muscular strength for female subjects were significantly lower than those of the male subjects. The predicted MET using the theoretical model, with a group constant k, was highly correlated with those using the empirical models compared in the current study.     

VELOCITY DISTRIBUTIONS AND ENERGY DISSIPATION FORTHE FLOW OF HIGHLY-VISCOUS FLUID IN THE AGITATED VESSEL WITH AN ANCHOR IMPELLER

The flow patterns and velocity distributions for the flow of highly-viscous fluid in the agitated vessel withan anchor impeller were obtained by means of streak photography using selective illumination of the vessel andpolystyrene pearl as tracer particle. Equations of velocity distribution,     

Kinetics of the methanation of carbon dioxide over a supported Ni-La2O3 catalyst

The kinetics of the methanation of carbon dioxide was investigated using an alumina supported Ni-La₂O₂ catalyst in a differential and integral reactor. In the differential reactor the molar ratio of H₂ to CO₂ was varied from 0.6 to 30. In the integral reactor the rates were measured with up to 90% conversion. Both reactor tests were carried out at temperatures between 513 and 593 K. The experimental results were described by a Langmuir-Hinshelwood type equation. The kinetics can be explained by assuming equilibrium of dissociative carbon dioxide and hydrogen adsorption, and assuming hydrogenation of surface carbon as the rate determining step.     

Managing knowledge on communication and information flow in global software projects

Communication is a key success factor of distributed software projects. Poor communication has been identified as a main obstacle to successful collaboration. Global projects are especially endangered by information gaps between collaborating sites. Different communication styles, technical equipment, and missing awareness of each other can cause severe problems. Knowledge about actual and desired channels, paths, and modes of communication is required for improving communication in a globally distributed project. However, many project participants know little about communication and information flow in their projects. In this contribution, we focus on knowledge about communication and information flow. It is acquired by modelling on‐going and desired flows of information, including documented and non‐documented channels of information flow. We analyzed a distributed software project from the information flow perspective. Based on the findings, we developed specific techniques to improve information flow in distributed software development according to the FLOW Method. In a second distributed project, we evaluated one of the techniques. We found the FLOW mapping technique to be suitable for effectively spreading knowledge about communication and information flow in global software projects.     

Effect of Silicon Dioxide on the Thermal Diffusivity of Aluminum Nitride Ceramics

The thermal diffusivity of AlN ceramics was significantly decreased by the addition of SiO₂. The AlN ceramics with 4 wt% SiO₂ could not be densified by pressureless sintering in the temperature range 1400° to 1800°C. The thermal diffusivity of these samples was very low because of their porous structure. The AlN ceramics containing 2, 4, and 8 wt% SiO₂ were densified by hot-pressing and also had low thermal diffusivity. In these samples, the grains of the 27R polytype that resulted from the reaction between AlN and SiO₂ were dispersed, obstructing the conduction of heat. The relation between the amount of 27R polytype and the thermal diffusivity of the AlN ceramics was determined.     

New approach for the preparation of nanoporous polyorganosilicate low‐k films

The distribution of pores and the mechanical properties of materials are the key factors in preparing satisfactory low‐k films. In the present study, a kind of silsesquioxane‐polyethylene glycol (SSQ‐PEG) was synthesized and used as a template to make the distribution of pores more even in the low‐k films. The crosslinking density of films could be adjusted by the sol‐gel of tetramethoxysilane/dimethoxydimethylsilane with various proportions. The porosity of films could also be adjusted with different proportions of pendant PEG chains introduced. A dielectric constant as low as 2.1 had been achieved for nanoporous polyorganosilicate films with good tenacity. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1238–1243, 2007     

高粘变物性流体管内传热的计算机仿真

对高粘变物性流体管内传热进行了计算机仿真。结果表明 :压力降受物性影响较大 ;采用较小管径是减小径向温差的有效措施