引进冷连轧机厚控系统分析及改进方案

武钢、宝钢两套冷连轧机代表了冷连轧技术发展水平 ,用连轧张力理论对这两套冷连轧机的厚控系统作了深入的分析、讨论 ,给出了其中最主要厚控环节 -连轧AGC和张力AGC的数学模型。对宝钢厚控系统提出了改进方案 ,利用DAGC可以简便地实现穿带、正常轧制、抛尾 ,而不用分别采用APC、恒压力、压力AGC三种控制方式 ,并且DAGC实现恒压力控制有更高的稳定性。     

冷轧无取向硅钢的织构和组织性能分析

分析和讨论了国内外牌号为50W800和50W600，50H1300，50A1300的4种普通冷轧无取向硅钢的成分、组织、织构对磁性的影响。根据织构取向分布函数(ODF)分析结果，得出为获得高的无取向硅钢磁性能，硅钢除具有高的纯净度，低的夹杂物含量，组织均匀、晶粒细小外，应控制产品形成{HKL}面织构，尤其是{100}面织构，以便同时降低铁损和提高磁感。     

304不锈钢冷轧卷连续钝化工艺参数的正交试验

用CIE1976L^*a^*b^*色空间中的白度HW^*作为不锈钢冷轧卷钝化后表面质量的评价指标，对304(18-8)奥氏体不锈钢板材的钝化工艺参数(HNO3 10％～20％，HF 0．8％～2．5％、钝化温度40～70℃、钝化时间1．0～3．0min)进行了正交试验和方差分析。试验和分析结果得出，不同炉批304不锈钢冷轧卷材，因成分和工艺差异，使板材最佳钝化工艺参数稍有不同，但从整体来看，304不锈钢卷材钝化的最佳工艺参数为：HNO3 10％～12％，HF 2．0％～2．5％，钝化温度40～50℃，钝化时间2．0～2．5min。     

不锈冷轧带钢表面光洁度的控制

在生产中，不锈冷轧带钢的表面光洁度一般用粗糙度进行控制，其粗糙度越低，光洁度越高。应使用低粗糙度和低微小缺陷面积率的不锈热轧带钢，高的总压下量，低粘度轧制油和平整率达到1％的工艺轧制可获得较高光洁度的不锈冷轧带钢。高速钢轧辊轧制的不锈冷轧带钢的光洁度优于模具钢轧辊。     

Field Investigation of Soil Heave by a Large Diameter Chilled Gas Pipeline Experiment, Fairbanks, Alaska

A large scale 105-m-long, 0.9-m-diam chilled pipeline experiment was conducted to assess the response of a production pipeline that transits between unfrozen (seasonally frozen) and permafrost soils in discontinuous permafrost regions. Thermal and heave characteristics of the experiment for a three-year monitoring period are reported. In response to the chilled pipeline, the progressive cooling patterns within the permafrost and unfrozen soils were different, resulting in the development of a thermal boundary at the transition zone between the two thermally different soils. The absolute maximum movement of pipeline was 0.197 m near the thermal boundary, resulting in a differential heave of 0.148 m. Three distinct heave phases were identified within the unfrozen soil. Phase 1 of the first 200 days related to penetration and heave above the groundwater table and was characterized by heave rates between 0.211 and 0.237 mm/day. Phase 2 resulted in increased ice segregation due to interaction of the freez-ing front with the groundwater table. This phase lasted from approximately day200 to day 500 and corresponded to a heave rate from 0.206 to 0.313 mm/day. Phase 3 was characterized by a further decrease in the heave rate to about 0.081 mm/day and lasted from approximately day 500 to day 1,056.     

In situ Sea Ice Experiments in McMurdo Sound: Cyclic Loading, Fracture, and Acoustic Emissions

The breakup of first-year sea ice plays an important role in the dynamics and thermodynamics of polar ice covers. A recent research program has studied the in situ mechanical properties of the annual ice in Antarctica to support the development of physically based models of the breakup process. As part of this effort, two field trips were conducted to McMurdo Sound, and the present paper describes the experimental work and presents selected results. The in situ experiments investigated the constitutive and fracture behavior of edge-notched, square plate specimens of first-year ice and involved a detailed characterization of the physical properties and thermal state of the ice. Acoustic emissions, which are generated by microcracking, were monitored in the crack tip vicinity and provide insight regarding the size of the process zone. The paper describes the physical properties and microstructure of the sheet, the cyclic-loading response, and the acoustic emissions activity from an extensive series of experiments conducted on one of the in situ specimens. Varying the cyclic-loading frequency and amplitude provided a means to examine rate effects on the anelastic and viscous components of strain and the extent of microcracking near the crack tip. The viscous deformation rate estimated from the experiments exhibited an increasing power-law exponent with values between one and three. Acoustic emissions monitoring indicated that microcracking occurred in a process zone near the crack tip, and the size of the process zone increased with decreasing cyclic loading frequency. Practical aspects of the experiments are considered, and the results are put into context with the overall modeling goals of the project.     

冷拉伸滚压成形新工艺参数研究

采用ADINA有限元软件对高强度柔性螺栓在此加工工艺中定义材料性能,建立滚压模型,划分网格,约束边界条件,施加载荷.对在不同拉力,滚压量两个实验参数下进行冷拉伸滚压新工艺加工模拟仿真,得到端面中点的最大应力,有效应力及位移与时间函数的图形,并分析结果得出最有利于加工的工艺参数.为下一步做轴类冷拉伸滚压成形实验提供重要的实验参数.     

Physical force-sensitive touch responses in liquid crystal-gated-organic field-effect transistors with polymer dipole control layers

We report the sensing performances of liquid crystal-gated-organic field-effect transistors with a polymer dipole layer (DCL-LC-g-OFETs) upon physical touches. The DCL-LC-g-OFET devices, which were fabricated by employing 4-cyano-4’-pentylbiphenyl (5CB) as a sensing gate insulating layer, poly(methyl methacrylate) (PMMA) DCL, and 50 nm-thick poly(3-hexylthiophene) (P3HT) channel layer, which were optically semi-transparent and exhibited p-type transistor behavior. A pencil-like load (0.6 g–4.8 g) was introduced as a means for physical touch, while a human finger was used to examine the practical sensing capability of devices. Results showed that the drain current responded quickly upon physical touch and increased linearly with the strength of physical touch. The response time upon physical touch was slightly affected by the touch strength but was as fast as less than 1 s, while the drain current signals were quite reproducible and stable even after repeated physical touches. The present DCL-LC-g-OFET devices exhibited excellent sensing performances and reproducibility upon the human finger touch.     

From experimental data,the mechanics relationships describing the behaviour of four different low alloyed steel powders during uniaxial cold compaction

This work aims at determining the constitutive model of four commercial water atomised low alloyed steel powders during cold compaction. Single-action experiments were performed, obtaining cylindrical specimens with different H/D ratios. The distribution of axial and radial stresses was investigated, and the relationships describing both the radial stress transmission coefficient and the flow stress as functions of the relative density were determined. The radial stress transmission coefficient also confirmed the hypothesised value of Poisson’s coefficient. The friction coefficient between the powder column and the die wall was determined, also highlighting the influence of the H/D ratio. Measuring the axial and radial strains due to spring-back, the axial and radial elastic moduli were determined, as functions of the relative density. The results obtained for the four materials were compared, also highlighting both differences and similarities.     

Influence of ring-type internals on the solids residence time distribution in the fuel reactor of a dual circulating fluidized bed system for chemical looping combustion

The intensification of gas-solids contact in the fuel reactor of a chemical looping combustion system is enhanced with the installation of ring-type internals. This can be a key issue for achieving the necessary fuel conversion rates. Wedged rings, previously designed and tested, were found to increase the particle concentration in the counter current section of the fuel reactor and hence, to achieve a more homogeneous particles concentration along this zone. The present work investigates the effect of the mentioned internals on the residence time distribution of particles in the fuel reactor of a dual circulating fluidized bed system for chemical looping. The study was carried out in a cold flow model especially designed for the fluid-dynamic analysis of the system equipped with a recently developed residence time measurement device based on the detection of ferromagnetic tracer particles through inductance measurement. Ring internals proved the positive effect on the particles residence time, the residence time distribution is more symmetric and shows lower dispersion, the flow pattern is more plug-flow-like, these effects are intensified with the reduction of the aperture ratio of the rings. On the other hand, the upward particle transport in the counter-current zone of the fuel reactor also increases with the installation of the rings, increasing the bypass flow of solids through the fuel reactor's return loop (internal circulation). For high internal circulation rates the solids residence time distribution of the fuel reactor is dominated by the bypass effect. The findings may be used for focused design improvement of the investigated fluidized bed system.