新型总线技术——RACEway和RapidIO概述

从传统的总线技术开始，主要介绍了两种新型的总线技术：RACEway和RapidIO及二者的比较，并探讨了其在实时应用系统中的未来发展趋势。

Surface Roughness and Roundness of Bearing Raceway Machined by Floating Abrasive Polishing and Their Effects on Bearing's Running Noise

As the two most important indexes of bearing raceway, surface roughness and roundness have significant influence on bearing noise. Some researchers have carried out studies in this field, however, reason and extent of the influence of raceway surface geometric characteristics on bearing running noise are not perfectly clear up to now. In this paper, the raceway of 6309 type bearing＇s inner and outer ring is machined by floating abrasive polishing adopting soft abrasive pad. Surface roughness parameters, arithmetical mean deviation of the profile Ra, the point height of irregularities Rz, maximum height of the profile Rmax and roundness fof raceways, are measured before and after machining, and the change rules of the measured results are studied. The study results show that the floating abrasive polishing can reduce the surface geometric errors of bearing raceway evidently. The roundness error is reduced by 25%, Rm^x value is reduced by 35.5%, Rz value is reduced by 22% and Ra value is reduced by 5%. By analyzing the change of the geometrical parameters and the shape difference of the raceway before and after machining, it is found that the floating abrasive polishing method can affect the roundness error mainly by modifying the local deviation of the raceway＇s surface profile. Bearings with different raceway surface geometrical parameter value are assembled and the running noise is tested. The test results show that Ra has a little, Rmax and Rz have a measurable, and the roundness error has a significant influence on the running noise. From the viewpoint of controlling bearings＇ running noise, raceway roundness error should be strictly controlled, and for the surface roughness parameters, R,n^x and Rz should be mainly controlled. This paper proposes an effective method to obtain the low noise bearing by machining the raceway with floating abrasive polishing after super finishing.

Radiant Image Simulation of Pulverized Coal Combustion in Blast Furnace Raceway

The relationship between two-dimensional radiant image and three-dimensional radiant energy in blast furnace raceway was studied by numerical simulation of combustion process. Taking radiant image as radiant boundary for numerical simulation of combustion process, the uneven radiation parameter can be calculated. A method to examine three-dimensional temperature distribution in blast furnace raceway was put forward by radiant image processing. The numeral temperature field matching the real combustion can be obtained by proposed numeric image processing technique.

Culturing of Autoflocculating Microalgal Consortium in Continuous Raceway Pond Reactor

The goal of this study was to develop a self-settling microalgal consortium in raceway pond reactor (RPR). Experiments were carried out with cultures that developed without additional seeding, but naturally promoted by process conditions in a raceway pond reactor. The changes in microalgal communities and total biomass under nitrogen and phosphorous limitations were studied in both batch and continuous systems. At the steady state batch had the population of 46% Euglena sp., 16% Closterium sp., 14% Chlorella sp., 14% Scenedesmus sp. and 10% Ankistrodesmus sp. with a maximum biomass of 900 mg/L. In order to get self-settling microalgal consortium, the operation was changed to continuous continuous mode with the aid of a specially designed settler for daily harvest and recycling of the biomass. Grazing fauna could be controlled by managing reduced liquid and solid retention time. At steady-state condition, an autofloculating and self-settling consortium was developed which had mainly Fragilaria sp., Scenedesmus sp., and filamentous Ulothrix sp. The maximum biomass concentration obtained was 140 mg/L. The presence of neutral lipid droplets in the consortium was identified by staining with Nile Red. Development of the lipid rich consortium could be a suitable method for producing biofuel.

A Novel Splash Plate Design for Serial Reuse Raceways

Serial reuse raceways in fish hatcheries typically use dam boards and screens to separate each raceway unit in the series. This paper describes a novel raceway splash plate constructed of aluminum plate and angle, which eliminates the need for screens when mounted on top of raceway dam boards. In addition to reducing the labor required to remove and replace, and clean screens, the splash plate increased the amount of available rearing space. Incoming water dissolved oxygen concentrations were also increased. These splash plates are relatively easy and inexpensive to fabricate, and their use can lead to increased efficiencies during hatchery rearing.

Optimization of Raceway Parameters in Iron Making Blast Furnace for Maximizing the Pulverized Coal Injection (PCI) Rate

This paper presents a method by which the maximum possible rate of pulverized coal injection (PCI) in blast furnace can be predicted. The method is based on a two-step approach. First, a first principle simulation model of the blast furnace is used to generate data sets for the development of a linear model of pulverized coal injection rate. The data has been generated randomly in MATLAB software within the range of operating parameters (constraints) of the blast furnace. After that, the coefficients of the function have been determined. The inputs and the resulting outputs formed the data on which the linear optimization model was developed. Next, the linear model was used for maximizing the pulverized coal rate injection by optimizing the other variables. Two operating Indian Blast Furnaces have been chosen to validate the optimization model.

CFD-DEM study on the synergistic effect of coke consumption and particle dynamics in the blast furnace raceway

In this study,the gas-solid flow process in the blast furnace raceway is numerically simulated using coupled computational fluid dynamics and the discrete element method(CFD-DEM).The coke reaction kinetics data are imported into the DEM model to reproduce the consumption process of each coke particle.The effects of inlet gas velocity and angle on the morphology of the raceway,coke consumption rate,coke bed temperature,and particle size distribution in the blast process are systematically investigated and analyzed.The results show that the consumption of coke particles promotes the formation of raceways during the blast process.At the same time,a coke mixture layer is produced at the edge of the raceway.The higher the inlet gas velocity,the thicker the coke mixture layer in the middle and upper parts of the raceway region,and the larger the proportion of small particles in the coke mixture layer.The effect of the inlet gas angle on the raceway region is less than the inlet gas velocity.However,with the increase in the inlet gas angle,the high-temperature region of the coke bed extends downward gradually,which is conducive to activating the hearth.

Cage slip characteristics of a cylindrical roller bearing with a trilobe-raceway

Based on dynamic analysis of rolling bearings, the nonlinear dynamic differential equations of a cylindrical roller bearing with a trilobe-raceway were established and solved by the GSTIFF（gear stiff） integer algorithm with a variable step. The influences of structural parameters and the tolerance of the trilobe-raceway, working conditions of the bearing, and the outer ring installation method on cage slip characteristics were investigated. The results show that：（i） The cage slip ratio and bearing rating life of a cylindrical roller bearing with a trilobe-raceway would reduce when the low-radius（radius of the outer raceway contour at the lowest point） and D-value（difference value between the high and low points of the outer raceway contour） decrease, and the former（low-radius） contributes more significantly.（ii） The cage slip ratio of a cylindrical roller bearing with a trilobe-raceway rises with the increase of the bearing speed, and decreases with the increase of the radial force; the variation range increases with the increase of the low-radius.（iii） When the installation angle of the outer ring increases in a period, the cage slip ratio remains unchanged while the bearing rating life rises up a little. Therefore, when installing a cylindrical roller bearing with a trilobe-raceway, the location of the maximum radius shall be under that of the radial force to improve the bearing rating life.（iv） With the increase of the roundness of the base circle where the radius of the lowest points of the trilobe-raceway contour locates, the cage slip ratio rises gradually and the bearing rating life decreases.

Gas-Particle Flow and Combustion Characteristics of Pulverized Coal Injection in Blast Furnace Raceway

The two-dimensional steady-state discrete phase mathematical model is developed to analyze gas-particle flow and combustion characteristics of coal particles, as well as components concentration and temperature distribu- tion of coal gas in the process of pulverized coal injection of blast furnace raceway. The results show that a great deal of coal gas discharges on the top of raceway away from the tuyere, and the residence time of coal particles in the re- gion of blowpipe and tuyere is 20 ms or so and 50 ms when it reaches raceway boundary. The pressure is the highest at the bottom of raceway and the maximal temperature is about 2 423 K. The char combustion is mainly carried out in the raceway and the maximum of char burn-out rate attains 3× 10-4 kg/s.

Mathematical Model Development of Raceway Parameters and Their Effects on Corex Process

Corex is an alternative ironmaking process and raceway is one of the important areas to maintain the stability of the furnace. The raceway parameters are well established for blast furnace operation. But for Corex process,it has not yet been established and optimized. Thus,a mathematical model was developed to determine various raceway parameters such as RAFT （raceway adiabatic flame temperature）,tuyere gas velocity and kinetic energy. The model provides an idea about the raceway geometry,zone temperature and kinetic energy accumulated in tuyere gas. Besides,all the raceway parameters have been analyzed to find out their effects on the Corex process. It is found that RAFT influences the gasification reaction kinetics and higher RAFT generates more CO in reduction gas,which improves the metallisation degree of the DRI in shaft. It is also found that increased gas velocity and kinetic energy generate more fines and demand more coke to maintain char bed permeability. High coke rate increases the production cost and lowers the production of hot metal.

Interaction mechanism between coal combustion products and coke in raceway of blast furnaces

The interaction mechanism between the combustion products of pulverized coal injected and coke in the raceway of blast furnace was studied through thermodynamic calculation and experiments.The results indicated that additives significantly affected the melting property of coal ash in high temperature zone.Although the unburnt char,raw coal ash,and catalyzed coal ash failed to wet the coke surface,the wettability of the catalyzed coal ash on the coke was greater than that of the raw coal ash.Since the unburnt char had weak reaction with the coke surface,it showed little influence on the surface morphology of the coke.The interaction between the raw coal ash and the coke gave rise to the increase in the pore size on the coke surface.However,the raw coal ash only affected the coke surface and the entrances of the pores owing to its poor fluidity.After being melted,the catalyzed coal ash was expected to immerge into the inside part of the coke and then react with the coke,resulting in an expansion and increase of coke cavities.The raw coal ash and the unburnt char reduced the coke reactivity,while the catalyzed coal ash improved the coke reactivity.Thereinto,the coal ash containing Fe2O3 exhibited a larger influence on the reactivity than that containing CaO.

Definition of Raceway Boundary Using Fractal Theory

The particle velocity contours were obtained by tracking the tracer particles in the raceway region of the COREX melter gasifier model and the contours were irregular. According to the fractal theory, the fractal dimen sions of different particle velocity contours were determined. Through the analysis of the fractal dimensions, a new method for precise determination of the raceway boundary was proposed. The results show that, when the velocity is less than 0.18 m/s, the particles are located in the stagnant zone and the fractal dimensions of particle velocity con- tours are almost constant as 1.41; when the velocity increases from 0.18 to 0.83 m/s, the particles are located in the rapid movement zone and the fractal dimensions decrease gradually from 1.41 to 1.05 ＇when the velocity is grea- ter than 0.83 m/s, the particles are located in the cavity zone and the fractal dimensions are again almost constant as approaching to 1.00. Therefore, the velocity contour of 0.18 m/s, which is critical to distinguish the rapid move- ment zone and stagnant zone, can be used to define the raceway boundary. Based on this method, the effect of blo wing rate on raceway size was calculated and the results show that the penetration depth and height of the raceway increase with the increase of blowing rate.

Cold Model of Coal Gas Component Concentration Distribution in Blast Furnace Raceway

Primary distribution of coal gas in blast furnace raceway has an important effect on blast furnace ironmaking process. The coal gas component concentration distribution was studied experimentally using a three-dimensional cold model. The results showed that CH4 concentration diminishes along with the height increasing on vertical section of raceway, and the concentration is the highest in the bottom of raceway. CH4 concentration increases gradually along.the raceway depth with the lowest concentration value in front of the tuyere. The distribution of CH4 concentration has different characteristics in different raceway zones.

Fractal Study on Raceway Boundary

The raceway has been studied extensively both theoretically and experimentally. The raceway boundary is coarse and fragmentary,but all of previous studies are based on Euclidean geometry,which regards the dimension of raceway as an integer. The fractal method of calculating raceway size,which describes boundary with extremely irregular or fragmentary characteristic,is brought forward in physical model. The fractal theory is used to calculate the fractal dimension of raceway boundary and the precise surface area of ellipsoidal raceway boundary. The result shows that the surface area based on fractal is larger than that based on Euclidean. And the surface area increases with the rise of blowing rate.

Lipid accumulation and CO_2 utilization of two marine oil-rich microalgal strains in response to CO_2 aeration

Biological CO2 sequestration by microalgae is a promising and environmentally friendly technology applied to sequester CO2. The characteristics of neutral lipid accumulation by two marine oil-rich microalgal strains,namely, Isochrysis galbana and Nannochloropsis sp., through CO2 enrichment cultivation were investigated in this study. The optimum culture conditions of the two microalgal strains are 10% CO2 and f medium. The maximum biomass productivity, total lipid content, maximum lipid productivity, carbon content, and CO2 fixation ability of the two microalgal strains were obtained. The corresponding parameters of the two strains were as follows：（（142.42±4.58） g/（m^2·d）,（149.92±1.80） g/（m^2·d））,（（39.95±0.77）%,（37.91±0.58）%）,（（84.47±1.56） g/（m^2·d）,（89.90±1.98） g/（m^2·d））,（（45.98±1.75）%,（46.88±2.01）%）, and（（33.74±1.65） g/（m^2·d）,（34.08±1.32） g/（m^2·d））. Results indicated that the two marine microalgal strains with high CO2 fixation ability are potential strains for marine biodiesel development coupled with CO2 emission reduction.

一种高速数字信号处理方法的研究

全文说明了现代实时运算对高速并行数字信号处理的需求,介绍了目前通用的几种高速数字信号处理器结构及其在雷达信号处理中的应用,叙述了实时高速数字信号处理的发展方向。

Study on the stability control technology of large-scaled blast furnaces

Nowadays,there are two major trends,which are the increasing blast furnace （BF） working volume and the decreasing fuel resource as well as the decline in its quality,in the ironmaking filed. The two trends lead to the difficulty in the BF operation. The decline of the BF stability requires higher and more elaborate operational techniques. A reasonable and compatible BF comprehensive operating system,as the base of the BF stabilization,is desired to satisfy the demand of large-scaled BF developments. Based on the practical operation of Baosteel No. 3 BF in 2010, the present work analyzes and discusses the basic rules of large-scaled BF stable control techniques,and further optimizes and improves its gas flow control techniques, develops strategies against the decline in fuel quality, which will contribute to the promotion of largescaled BF operational techniques progress.