Actuator and sensor failure detection using direct approach

Li, Zhiling,Nagarajaiah, Satish Techno-Press 2014 Structural monitoring and maintenance Vol.1 No.2

A novel real-time actuator failure detection algorithm is developed in this paper. Actuator fails when the input to the structure is different from the commanded one. Previous research has shown that one error function can be formulated for each actuator through interaction matrix method. For output without noise, non-zero values in the actuator functions indicate the instant failure of the actuator regardless the working status of other actuators. In this paper, it is further demonstrated that the actuator's error function coefficients will be directly calculated from the healthy input of the examined actuator and all outputs. Hence, the need for structural information is no longer needed. This approach is termed as direct method. Experimental results from a NASA eight bay truss show the successful application of the direct method for isolating and identifying the real-time actuator failure. Further, it is shown that the developed method can be used for real-time sensor failure detection.

Memory characteristics and tunneling mechanism of Pt nano-crystals embedded in HfAlOx films for nonvolatile flash memory devices

Guangdong Zhou,BoWu,Zhiling Li,Zhijun Xiao,Shuhui Li,Ping Li 한국물리학회 2015 Current Applied Physics Vol.15 No.3

A non-volatile flash memory device based on metal oxide semiconductor (MOS) capacitor structure hasbeen fabricated using platinum nano-crystals(PteNCs) as storage units embedded in HfAlOx high-ktunneling layers. Its memory characteristics and tunneling mechanism are characterized by capacitanceevoltage(CeV) and flat-band voltage-time(ΔVFB-T) measurements. A 6.5 V flat-band voltage(memory window) corresponding to the stored charge density of 2.29 × 1013 cm-2 and about 88% storedelectron reserved after apply ±8 V program or erase voltage for 105 s at high frequency of 1 MHz wasdemonstrated. Investigation of leakage currentevoltage(JeV) indicated that defects-enhanced Pool-Frenkel tunneling plays an important role in the tunneling mechanism for the storage charges. Hence,the PteNCs and HfAlOx based MOS structure has a promising application in non-volatile flash memorydevices.

Genetic Diversity, Population Genetic Structure and Protection Strategies for Houpoëa officinalis (Magnoliaceae), an Endangered Chinese Medical Plant

Li Huogen,Yang Xu,Yang Zhiling 한국식물학회 2018 Journal of Plant Biology Vol.61 No.3

Houpoëa officinalis is a traditional Chinese medicalplant, which has significantly declined in the past decadesbecause of human influence and habitat fragmentation. Twelveexpressed sequence tag SSR (EST-SSR) markers developedfrom the EST sequence of H. officinalis were used to analysethe genetic diversity and structure of fourteen naturalpopulations. The results indicated that moderate geneticdiversity and high genetic differentiation existed in this plant(Ho = 0.600, Fst = 0.327). STRUCTURE and UPGMAanalyses showed that H. officinalis populations could bedivided into 3 different groups, and the west group hadhigher genetic diversity than the central and east groups. Thehistorical migration rates among the groups were low andunsymmetrical, and there was no significant correlation betweenNei’s genetic distance and geographic distance. According to thegenetic consequences, conservation strategies (in situ or ex situ,artificial pollination) should be carried out in all populationsto preserve genetic diversity.

Epidemic Model based Security Analysis of Firefly Clock Synchronization in Wireless Sensor Networks

Zhiling Tang,Simin Li 보안공학연구지원센터 2015 International Journal of Security and Its Applicat Vol.9 No.6

This paper discusses the security of the clock synchronization algorithm based on the biological example of Asian Fireflies in wireless sensor networks. Huge swarms of these fireflies use the principle of pulse coupled oscillators in order to synchronously emit light flashes to attract mating partners. When applying this algorithm to real sensor networks, the potential threat of hostile flashes may disturb this synchronization. An improved Reachback Firefly Algorithm is implemented in the MAC layer of wireless sensor networks (WSNs), which change coupling strength among oscillators to anti hostile attack in clock synchronization. Its security is analyzed through a Susceptible-Infective-Recovered epidemic model. Numerical results and simulations are provided for further understanding of the analysis.

Convention Industry in Beijing : an Engine to World City Formation

Zhou, Yan,Li, Zhiling 한국무역전시학회 2012 무역전시연구 Vol.7 No.1

Oxidative damage-induced hyperactive ribosome biogenesis participates in tumorigenesis of offspring by cross-interacting with the Wnt and TGF-β1 pathways in IVF embryos

Huang Yue,Li Zhiling,Lin En,He Pei,Ru Gaizhen 생화학분자생물학회 2021 Experimental and molecular medicine Vol.53 No.-

In vitro fertilization (IVF) increases the risk of tumorigenesis in offspring. The increased oxidative damage during IVF may be involved in tumor formation. However, the molecular mechanisms underlying this phenomenon remain largely unclear. Using a well-established model of oxidatively damaged IVF mouse embryos, we applied the iTRAQ method to identify proteins differentially expressed between control and oxidatively damaged zygotes and explored the possible tumorigenic mechanisms, especially with regard to the effects of oxidative damage on ribosome biogenesis closely related to tumorigenesis. The iTRAQ results revealed that ribosomal proteins were upregulated by oxidative stress through the Nucleolin/β-Catenin/n-Myc pathway, which stimulated ribosomes to synthesize an abundance of repair proteins to correct the damaged DNA/chromosomes in IVF-derived embryos. However, the increased percentages of γH2AX-positive cells and apoptotic cells in the blastocyst suggested that DNA repair was insufficient, resulting in aberrant ribosome biogenesis. Overexpression of ribosomal proteins, particularly Rpl15, which gradually increased from the 1-cell to 8-cell stages, indicated persistent hyperactivation of ribosome biogenesis, which promoted tumorigenesis in offspring derived from oxidatively damaged IVF embryos by selectively enhancing the translation of β-Catenin and TGF-β1. The antioxidant epigallocatechin-3-gallate (EGCG) was added to the in vitro culture medium to protect embryos from oxidative damage, and the expression of ribosome-/tumor-related proteins returned to normal after EGCG treatment. This study suggests that regulation of ribosome biogenesis by EGCG may be a means of preventing tumor formation in human IVF-derived offspring, providing a scientific basis for optimizing in vitro culture conditions and improving human-assisted reproductive technology.

Influence of crosslinker amount on swelling and gel properties of hectorite/poly(acrylamide/itaconic acid) nanocomposite hydrogels

Tao Wan,Wenzhong Cheng,Zhiling Zhou,Min Xu,Chuzhang Zou,Ruixiang Li 한국화학공학회 2015 Korean Journal of Chemical Engineering Vol.32 No.7

A new hectorite/poly(acrylamide/itaconic acid) nanocomposite hydrogel was synthesized by inverse microemulsion polymerization. The effects of crosslinker amount on water absorbency and salt absorbency, swellability, pHsensitivity, gel strength, temperature-and shear-resistance were investigated. Water and salt absorbencies, pH-sensitivity and swellability decreased, while gel strength and temperature-and shear-resistance increased with increasing crosslinker amount. Nanocomposite hydrogels had good thermal stability with onset decomposing temperature of 252 oC. The as-synthesized hydrogel particles were regular and spherical-like and had an average particle size of 43 nm in the range of 30-65 nm. Hectorite clay platelets were exfoliated and transformed into amorphous structure.

A novel lattice structure topology optimization method with extreme anisotropic lattice properties

Zhang Chenghu,Liu Jikai,Yuan Zhiling,Xu Shuzhi,Zou Bin,Li Lei,Ma Yongsheng 한국CDE학회 2021 Journal of computational design and engineering Vol.8 No.5

This research presents a lattice structure topology optimization (LSTO) method that significantly expands the design space by creating a novel candidate lattice that assesses an extremely large range of effective material properties. About the details, topology optimization is employed to design lattices with extreme directional tensile or shear properties subject to different volume fraction limits and the optimized lattices are categorized into groups according to their dominating properties. The novel candidate lattice is developed by combining the optimized elementary lattices, by picking up one from each group, and then parametrized with the elementary lattice relative densities. In this way, the LSTO design space is greatly expanded for the ever increased accessible material property range. Moreover, the effective material constitutive model of the candidate lattice subject to different elementary lattice combinations is pre-established so as to eliminate the tedious in-process repetitive homogenization. Finally, a few numerical examples and experiments are explored to validate the effectiveness of the proposed method. The superiority of the proposed method is proved through comparing with a few existing LSTO methods. The options of concurrent structural topology and lattice optimization are also explored for further enhancement of the mechanical performance.