ESW激波吹灰器在余热锅炉的应用

介绍了ESW激波吹灰器的工作原理及其在茂名分公司Ⅲ套催化裂化装置余热锅炉的应用情况。应用结果表明，使用ESW激波吹灰器吹灰效果明显，吹灰后余热锅炉排烟温度可下降29℃，过热蒸汽产量增加7t/h，锅炉自产饱和蒸汽产量增加2t/h，有效提高了余热锅炉的传热效率和过热能力，节能效果显著。对应用中出现的一些问题提出了改进建议。     

Sintering of an ultra pure α-alumina powder: I. Densification,grain growth and sintering path

Sintering in air of an ultra pure α-alumina powder has been investigated. Isothermal experiments have been conducted on green samples shaped by slip casting. The grain growth and densification kinetics have been established. The “relative density/grain size” trajectory, called “sintering path”, has been drawn. Hypotheses concerning the mechanisms controlling grain growth and densification have been formulated. For the first time, it is shown that grain growth and densification kinetics exhibit two distinct regimes, where an initial point defect formation step plays a key role. When point defects have been generated, the diffusion of the associated Al³⁺ cations controls grain growth and densification.     

Quality of manual data collection in Java software: an empirical investigation

Data collection, both automatic and manual, lies at the heart of all empirical studies. The quality of data collected from software informs decisions on maintenance, testing and wider issues such as the need for system re-engineering. While of the two types stated, automatic data collection is preferable, there are numerous occasions when manual data collection is unavoidable. Yet, very little evidence exists to assess the error-proneness of the latter. Herein, we investigate the extent to which manual data collection for Java software compared with its automatic counterpart for the same data. We investigate three hypotheses relating to the difference between automated and manual data collection. Five Java systems were used to support our investigation. Results showed that, as expected, manual data collection was error-prone, but nowhere near the extent we had initially envisaged. Key indicators of mistakes in manual data collection were found to be poor developer coding style, poor adherence to sound OO coding principles, and the existence of relatively large classes in some systems. Some interesting results were found relating to the collection of public class features and the types of error made during manual data collection. The study thus offers an insight into some of the typical problems associated with collecting data manually; more significantly, it highlights the problems that poorly written systems have on the quality of visually extracted data.     

Two topographic maps for data visualisation

We review a new form of self-organizing map which is based on a nonlinear projection of latent points into data space, identical to that performed in the Generative Topographic Mapping (GTM) [Bishop et al. (1997) Neurl Comput 10(1): 215–234]. But whereas the GTM is an extension of a mixture of experts, our new model is an extension of a product of experts [Hinton (2000) Technical report GCNU TR 2000-004, Gatsby Computational Neuroscience Unit, University College, London]. We show visualisation results on some real data sets and compare with the GTM. We then introduce a second mapping based on harmonic averages and show that it too creates a topographic mapping of the data. We compare these mappings on real and artificial data sets. Responsible editor: Soumen Chakrabarti.     

Environment as a first class abstraction in multiagent systems

The current practice in multiagent systems typically associates the environment with resources that are external to agents and their communication infrastructure. Advanced uses of the environment include infrastructures for indirect coordination, such as digital pheromones, or support for governed interaction in electronic institutions. Yet, in general, the notion of environment is not well defined. Functionalities of the environment are often dealt with implicitly or in an ad hoc manner. This is not only poor engineering practice, it also hinders engineers to exploit the full potential of the environment in multiagent systems. In this paper, we put forward the environment as an explicit part of multiagent systems.We give a definition stating that the environment in a multiagent system is a first-class abstraction with dual roles: (1) the environment provides the surrounding conditions for agents to exist, which implies that the environment is an essential part of every multiagent system, and (2) the environment provides an exploitable design abstraction for building multiagent system applications. We discuss the responsibilities of such an environment in multiagent systems and we present a reference model for the environment that can serve as a basis for environment engineering. To illustrate the power of the environment as a design abstraction, we show how the environment is successfully exploited in a real world application. Considering the environment as a first-class abstraction in multiagent systems opens up new horizons for research and development in multiagent systems.     

谈合理布局我国铝工业问题

文章分析了我国铝工业特别是电解铝工业布局的变化及其总布局战略思考的转变过程,并从铝工业特别是电解铝工业与合理开发利用我国能源资源 合理的铝工业链以及环保等方面的关系,论述了我国迫切需要统一思想,制定出一个科学合理的铝工业总体布局产业政策以及能保证其能正确实施的经济、法律手段。     

A globally convergent algorithm for transportation continuous network design problem

The continuous network design problem (CNDP) is characterized by a bilevel programming model, in which the upper level problem is generally to minimize the total system cost under limited expenditure, while at the lower level the network users make choices with regard to route conditions following the user equilibrium principle. In this paper, the bilevel programming model for CNDP is transformed into a single level convex programming problem by virtue of an optimal-value function tool and the relationship between System Optimum (SO) and User Equilibrium (UE). By exploring the inherent nature of the CNDP, the optimal-value function for the lower level user equilibrium problem is proved to be continuously differentiable and its derivative in link capacity enhancement can be obtained efficiently by implementing user equilibrium assignment subroutine. However, the reaction (or response) function between the upper and lower level problem is implicit and its gradient is difficult to obtain. Although, here we approximately express the gradient with the difference concept at each iteration, based on the method of successive averages (MSA), we propose a globally convergent algorithm to solve the single level convex programming problem. Comparing with widely used heuristic algorithms, such as sensitivity analysis based (SAB) method, the proposed algorithm needs not strong hypothesis conditions and complex computation for the inverse matrix. Finally, a numerical example is presented to compare the proposed method with some existing algorithms.     

Precipitation of barium sulfate nanoparticles via impinging streams

The impinging streams technology (abbreviated as IS) has good micromixing in the precipitation processes. The experiments were loaded with two reactants, BaCl₂ and Na₂SO₄, to prepare BaSO₄ in the impinging streams reactor, comparing with those in the direct precipitation (DP) reactor. XRD and TEM were used to analyze the crystal type, the morphology and size of particles through the photographs. The results indicate the size of the particles from IS is about 30 nm and of narrower distribution and finer dispersibility than that from DP.     

An analytical model to determine the ultimate load on masonry arch bridges.

This paper proposes an analytical elasto–plastic model to describe the behavior of arches. The modeling is carried out using the equations of (i) horizontal equilibrium, (ii) vertical equilibrium and (iii) equilibrium of moments. The latter equations of equilibrium are ordinary differential equations which can easily be solved by adding boundary conditions, imposing restrictions on the horizontal and vertical movement and on the rotation in the abutments of the arch. For masonry arches, including material properties allowing the occurrence of cracks and the subsequent formation of hinges is required. The latter theory has been implemented in a computer program (Matlab), offering numerical simulations. The software was used to illustrate two case-studies, i.e., the assessment of an arch loaded with a vertical point load and one with a horizontal point load.