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81.
In order to diagnose the working status of each module on sensor node and make sure the wireless sensor networks (WSN) work properly, the components of sensor node and their working characteristics are studied. An on-line fault self-diagnosis method for sensor node is proposed. First, a flexible fault sensing circuit is designed as a state detection module on sensor node. Second, a self-diagnosis algorithm is proposed based on the hardware design and the failure analysis on sensor node. Finally, in order to ensure the WSN reliability, the voltage changes of each module working statuses can be observed using the state detection module and the faulty module will be found out timely. The experimental results show that this self-diagnosis method is suitable to sensor nodes in WSN. 相似文献
82.
83.
将虚拟装配技术引入化工流程中,对可视化设计化工流程、培训工人操作技能以及化工厂的数字化建设具有很大的应用价值。通过分析精馏系统,搭建了可视化装配平台。根据装配约束条件建立了可装配设备模型。提出了"1+1"和"1+n"普遍化的装配方法,实现了装配复杂精馏系统。通过输出装配信息,获取精馏系统装配过程中的装配方式和装配序列,验证装配操作的正确性。装配测试表明装配方法正确可行,其真实性、准确性和有效性满足了精馏系统虚拟装配的要求,实现了自由选择设备装配所需的精馏系统。系统可扩展性强,通过添加其它单元设备,可以实现所有化工流程的虚拟装配。 相似文献
84.
王庆国 《武汉化工学院学报》2006,28(2):46-48
在肯定模糊评判方法的优点的基础上,对利用模糊评判方法进行地图产品质量评价结果的可靠性问题进行了探讨. 相似文献
85.
《Materials Research Bulletin》2006,41(1):29-37
The photoluminescence (PL) and vacuum ultraviolet (VUV) excitation properties are studied for the BaZr(BO3)2:Eu3+ phosphor with incorporating the Al3+, La3+, or Y3+ ion into the lattice. The excitation spectrum shows an absorption band in the VUV region with the band-edge at 200 nm and a very weak charge transfer band of Eu3+ at about 226 nm. The luminescence spectrum shows a strong emission at 615 nm (5D0 → 7F2 transition) and weak emission at 594 nm (5D0 → 7F1 transition) in BaZr(BO3)2:Eu3+, with a good red color purity. The PL intensity is increased by incorporating Al3+ into the BaZr(BO3)2 lattice. The PL intensity has also increased by incorporating La3+ into the lattice, however, the red color purity has deteriorated because of the increased centrosymmetric nature of the site. With the incorporation of Y3+ into the BaZr(BO3)2 lattice, the PL characteristics of the Eu3+ activator resembles that in the YBO3 lattices. The intensity of the red PL for the Eu3+ activator is the highest with good color purity for BaZr(BO3)2:Eu3+ incorporated with both Al3+ (10%) and La3+ (0.5%). 相似文献
86.
《Materials Research Bulletin》2006,41(4):867-872
A novel green emitting phosphor, Tb3+-doped Ca2GeO4 was prepared for the first time by a solid-state reaction. The phosphor showed prominent luminescence in green due to the magnetic dipole transition of 5D4 → 7F5. Structural characterization of the luminescent material was carried out with X-ray powder diffraction (XRD) analysis and field emission scanning electron microscopy (FE-SEM). Luminescence properties were analyzed by measuring the excitation and photoluminescence spectra. Photoluminescence measurements indicated that the phosphor exhibited bright green emission at about 541 and 550 nm under UV excitation. In addition, Al3+ or Li+ co-doping enhances the green emission from Ca2GeO4:Tb3+ by about 18 and 4 times, respectively, under UV excitation. The excellent luminescence properties make it a possible candidate for flat panel display application. 相似文献
87.
硅酸盐细菌在资源工程中的应用研究现状 总被引:7,自引:0,他引:7
对硅酸盐细菌的特性及在矿物加工领域中的应用现状作了较全面的综述;重点概括了硅酸盐细菌用于分解矿物、提取有价金属、矿石除杂、浮选、水处理等矿物加工方面的最新进展;同时,对硅酸盐细菌的解矿机理及在溶矿方面应用存在的问题进行了分析。 相似文献
88.
The effects of overcharge on electrochemical performance of AA size sealed-type nickel/metal hydride(Ni/MH) batteries and its degradation mechanism were investigated. The results indicated that the relationship between the effects of different overcharge currents on the increasing velocity of inner pressure and the degradation velocity of cycle life and discharge voltage remains in almost direct proportion. After overcharge cycles, the positive electrode materials remain the original structure, but there occur some breaks because of the irreversible expand of crystal lattice. And the negative electrode alloy particles have inconspicuous pulverization, but are covered with lots of corrosive products and its main component is rare earth hydroxide or oxide. These are all the main reasons leading to the degradation behavior of the discharge capacity and cycle life of Ni/MH batteries. 相似文献
89.
计算了N,N,N’,N’-四丁基-3-氧-戊二酰胺(N,N,N’,N’-tetrabutyl-3-oxa-pentanediamide,TBOPDA)中各个原子的电荷分布,根据电荷分布情况讨论了TBOPDA中有关化学键的相对稳定性和可能断裂几率,认为TBOPDA中化学键的辐照稳定程度为C-O〈C-H〈C-N〈C-C。理论推测的结果与相关辐解产物的产额顺序基本一致。 相似文献
90.
《Annals of Nuclear Energy》2005,32(3):253-260
We introduce a method for calculating the neutron flux around a finite number of spheres arranged in-line. The method uses the concept of superposition in which the solution for a group of spheres is composed of a sum of solutions for the individual spheres. We illustrate the method by a simple example based on a chain of highly absorbing spheres in a non-absorbing moderator and show that it converges rapidly to the exact solution. 相似文献