正交检测方法在钢铁铸造中的应用

在设计一种基于预测控制器模型时，最关键的工作是识别一个合理可靠的过程模型。在钢铁厂的连续铸造线上识别铸模液位模型是很困难的，由于极高的随机干扰水平，使得众所周知的随机阶跃函数，ＰＲＢＳ或随机试验输入等参数识别方法都以失败告终。而本文介绍的基于正交检测的方法给出了令人满意的结果。     

电源SoC:或许是好用的“疯狂”创意

对于电源管理IC,把包括开关、控制和无源元件在内的整个电源安装在一块芯片上,就能促成更高的功率效率,并降低散热量。尖端的电源拓扑结构、微型磁性元件、更快的开关器件可以共同使单片电源成为现实。     

18F]fluoroethoxy-benzovesamicol, a PET radiotracer for the vesicular acetylcholine transporter and cholinergic synapses

CACO-2 BBE was used to determine the response of a gastrointestinal epithelium to tumor necrosis factor-alpha (TNF). Incubation of CACO-2 BBE with TNF did not produce any effect on transepithelial resistance (TER) within the first 6 hr but resulted in a 40-50% reduction in TER and a 30% decrease in 1SC (short circuit current) relative to time-matched control at 24 hr. The decrease in TER was sustained up to 1 week following treatment with TNF and was not associated with a significant increase in the transepithelial flux of [14C]-D-mannitol or the penetration of ruthenium red into the lateral intercellular space. Dilution potential and transepithelial 22Na+ flux studies demonstrated that TNF-treatment of CACO-2 BBE cell sheets increased the paracellular permeability of the epithelium to Na+ and Cl-. The increased transepithelial permeability did not associate with an increase in the incidence of apoptosis. However, there was a TNF-dependent increase in [3H]-thymidine labeling that was not accompanied by a change in DNA content of the cell sheet. The increase in transepithelial permeability was concluded to be across the tight junction because: (i) 1 mM apical amiloride reduced the basolateral to apical flux of 22Na+, and (ii) dilution potential studies revealed a bidirectionally increased permeability to both Na+ and Cl-. These data suggest that the increase in transepithelial permeability across TNF-treated CACO-2 BBE cell sheets arises from an alteration in the charge selectivity of the paracellular conductive pathway that is not accompanied by a change in its size selectivity.     

Relationship between the anisotropy tensor calculated through global and object measurements in high-resolution X-ray tomography on cellular and composite materials

Structural anisotropy of two-phase materials can be evaluated through global measurements, as volume orientation or mean-intercept length methods do, or through statistics performed on a set of individual measurements. This last procedure is encouraged by recent improvements in the spatial resolution of conventional X-ray tomography. In this paper, the above-described approaches were compared in three case studies: a foam subjected to an in situ compression test, a second foam with a completely different cell morphology and a plastic material reinforced with short fibres. The approach based on the subdivision into distinguishable objects of the considered material phase has proved to be more sensitive in highlighting small deformations in the structure or small irregularities in an otherwise isotropic structure. On the other hand, the other approach is more general and is always usable. The two methods for calculating the fabric tensor tend to converge as the average anisotropy of individual objects in the statistical population increases. The use of Lambert's cylindrical equal-area projection of cell/fibre directions or local volume orientations is suggested, because the density of points is preserved from the sphere to the plane surface. Finally, a quick vector method to evaluate the anisotropy of the directions distribution has been presented, by defining a coherence index of the average direction.     

VOLTAGE COLLAPSE AND CONTROL ACTIONS: EFFECTS AND LIMITATIONS

ABSTRACT

This paper focuses on control actions determination for voltage collapse prevention. Sensitivity matrices are proposed based on the knowledge of the critical bus. By critical bus one means that bus whose state variables vary at most at the voltage collapse point. A tangent vector is used to identify the critical bus, and its behavior as a function of load increase is also investigated and compared with other indices previously proposed. It is shown that generator control actions may not work to increase voltage collapse margin, whereas local control actions may produce better results. The tests are carried out in the IEEE-300 bus test system, with and without reactive power limits consideration.     

微波塔引发配电线路雷电事故的分析

通过对微波塔易遭雷击以及微波塔引发配电线路雷电事故进行原因分析,阐述了对配电线路造成的后果和防范措施.通过案例事故,论述产生直击雷和感应雷的原因,同时论证两种雷电过电压对配电网络的危害和幅值大小,最后论述了防范此类事故的有效措施.实践表明:采取必要的防雷措施,是避免雷击,降低雷击危害的有效手段.     

核电循环冷却水一氯胺反应动力学规律

核电站循环冷却水系统的消毒是核电水系统的研究重点．以法国丹皮尔核电站冷却塔模型为研究对象,进行一氯胺消毒剂的消耗动力学研究,确定以天然原水为循环水介质的一氯胺消耗动力学符合一级反应的动力学模型,其反应速率常数为0．002min^-1;以人工模拟投加Fe^3＋进行一氯胺消耗分析表明,Fe^3＋对一氯胺的消耗无显著影响．     

纤维的结构和性能（Ⅷ）

继续前报内容介绍高速纺丝Ｎｙｌｏｎ６纤维的结构和性能：密度随纺丝速度而变化，以有纤维的Ｘ射线衍射图像，晶型和力学性质。