Evolution axiale du coefficient de transfert de matière en colonne à bulles et en lit fluidisé triphasique

Liquid phase volumetric mass transfer coefficients for oxygen are determined in a three-phase fluidized bed and in a bubble column. The concept of exponential decreasing axial variation of volumetric mass transfer coefficient leads to a better representation of oxygen concentration profiles inside the column. Compared to the bubble column, k_la axial variations are more important in the lower part of the fluidized bed column, where solid particles increase the coalescence phenomenum, particularly with viscous liquids.     

Measurement of residual stresses in injection‐molded polymer parts by time‐resolved fluorescence

Time‐resolved fluorescence properties of 9‐methylanthracene (9MAn) dispersed in film of polyvinylchloride (PVC) containing carbon black were studied under tensile loadings. The fluorescence lifetime of 9MAn decreased from 5.70 to 5.55 ns, whereas the stresses acting on the films increased from 0 to 3 MPa. The change in fluorescence lifetimes of 9MAn during the stress relaxation process showed that the fluorescence lifetimes were correlated with the stresses, not with the strains. The results suggest that 9MAn is a useful probe for monitoring stresses acting on the matrix. With the use of the fluorescence properties of 9MAn, the residual tensile stresses on the skin‐layer of PVC injection‐molded test pieces were estimated. The estimated residual stresses were about ～ 1 MPa. The residual stresses were relaxed to 0 MPa with annealing at 100°C. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2600–2603, 2002     

基于ARM9的自适应模糊PID定长切割控制系统

针对管材在线定长切割过程中位置和速度跟踪控制的难点问题,研发了以基于ARM9 S3C2416微处理器的控制器为核心的定长切割控制系统,并且采用基于自适应模糊PID控制器的伺服闭环控制系统,实现了管材定长切割的高精度控制。主要讨论了定长切割控制系统的硬件和软件设计、伺服系统建模、自适应模糊PID伺服跟踪技术的应用。实践证明:该控制系统采用触摸屏代替PLC,功能稳定,实时性高,操作灵活方便;采用自适应模糊PID控制器可明显提高其动态响应性能及定长切割的精度,使控制系统具有成本低、可靠性高、抗干扰能力强、控制精度高等优点,能够满足定长切割的精度要求。     

动态数学形态学轮廓提取算法在ARM上的实现

提出一种新的基于动态数学形态学的动态腐蚀轮廓提取算法。该算法以动态数学形态学中的约束条件为判断准则,通过定义评价函数来动态确定结构元素的移动方向,直接对感兴趣的目标进行轮廓提取。该算法引入自适应滤波门限,进一步增强了其抗噪处理能力。通过在ARM上对算法进行实现,得到了清晰的人体轮廓图像。该算法对实时目标的轮廓提取具有快速性和准确性的特点。     

用于测定钢液低氧含量的双层固体电解质研究

采用“毛坯浆料法”在ＺｒＯ２（９％摩尔含量ＭｇＯ）管状固体电解质基体表面制备了厚度为１－４μｍ的ＺｒＯ２（１０％摩尔含量Ｙ２Ｏ３）固体电解质涂层，并分别对此在本实验室和美国ＬｅｅｄｓａｎｄＮｏｒｔｈｒｕｐ公司进行了钢液低氧含量测试，结果表明：涂层没有破坏基体的抗热震性：氧浓差电池电动势的重现性偏差由原来的±２ｍＶ；电动势的绝对值提高１０ｍＶ左右；而比日本Ｔｏｒａｙ公司的同类产品提高３５ｍＶ，这说明     

9-蒽甲酸/卟啉钯衍生物的pH响应上转换性能

以9-蒽甲酸(9-ACA)为发光剂,八乙基卟啉钯(Pd OEP)为光敏剂,在二者最佳配比〔n(9-ACA)∶n(Pd OEP)=80∶1〕下,构建了对溶液中氢离子和氢氧根离子具备灵敏响应性的上转换发光体系9-ACA/PdOEP。当pH处于4～8以及8～11时,上转换发光强度均与pH呈现良好的线性关系。参比实验中,单一组分9-ACA本身的荧光强度与pH没有呈现线性关系,证明了9-ACA/Pd OEP体系对于pH的宽范围响应来源于光敏剂与发光剂之间的三线态-三线态能量转移(TTET)过程。     

基于ARM及嵌入式操作系统的电力通信管理机设计

针对变电站自动化系统中不同通信网络和通信协议间的互操作问题,提出了采用通信处理机的解决方案。基于ARM平台采用嵌入式以太网技术和嵌入式实时操作系统,设计了一种具有多种通信接口、能实现异种网络互联的通信管理机,阐述了通信管理机的功能和设计原则,介绍了系统的软、硬件设计实现。现场实际运行证明,设计的通信管理机功能上具备实时、可靠、可扩展、丰富网络支持等属性,运行稳定,是通信管理机发展的新方向。     

设置进程检查点的嵌入式容错系统设计

针对嵌入式Linux系统的特点,通过设置检查点(checkpoint)实现ARM平台进程级容错。在检查点工作时,通过/proc文件系统与内核进行交互,实时地获取与进程有关的PID、CPU状态以及内存信息,并保存在存储介质中。当进程出现故障后,将上述与进程有关的状态信息进行恢复,从而实现进程级容错。实验表明,该进程级容错系统有较好的容错能力,极大地缩短了进程恢复的时间。     

嵌入式Linux系统下CC1101的驱动与应用

CC1101在工业及实验室均有着广泛的应用,本文完成了基于ARM9硬件平台和嵌入式Linux系统的CC1101驱动开发,并以此为基础提出一种简单面向连接的通信模型。经验证,这种通信模型能够保证CC1101的通信质量。     

Electrical conductivity and redox stability of La2Mo2−xWxO9 materials

A series of compounds La₂Mo_2−xW_xO₉ (x = 0-2) were synthesized using a freeze-dried precursor method at relatively low temperatures (673-823 K). These materials were characterised by thermogravimetric and differential thermal analysis (TG/DTA), differential scanning calorimetric (DSC), X-ray diffraction (XRD), and transmission electron microscopy (TEM) and dilatometric measurements. Oxygen stoichiometry was evaluated by coulometric titration and thermogravimetric analysis at 873-1273 K. The ionic and electronic conductivities of these materials were analysed by impedance spectroscopy and a Hebb-Wagner ion-blocking method under moderately reducing conditions. The presence of W⁶⁺ leads to an increase of the stability range (about 10⁻¹⁶ Pa for La₂Mo_0.5W_1.5O₉ at 1073 K) and prevents oxygen loss and amorphisation. Within the stability range, the electronic conductivity increases gradually as the temperature increases and as the oxygen partial pressure reduces. This indicates that the electronic transport is mainly n-type as a result of the oxygen-content decreasing in the molybdate lattice. Further reduction of the oxygen partial pressure gave rise to the decomposition of La₂Mo_2−xW_xO₉, leading to the formation of new phases with molybdenum in lower oxidation states, which further enhances the electronic conductivity. The results of the coulometric titration and the thermogravimetric studies under a dry 5% H₂/Ar flow suggest that tungsten doped lanthanum molybdate materials can be used as electrolyte only at low temperature and under moderate reducing conditions.