Phase transition, dielectric and piezoelectric properties of NaNbO3-Bi0.5Li0.5TiO3 lead-free ceramics

Lingling Fu,Dunmin Lin,Qiaoji Zheng,Xiaochun Wu,Lang Wu,Hailing Sun,Yang Wan,Ximing Fan,Chenggang Xu 한국물리학회 2012 Current Applied Physics Vol.12 No.6

Lead-free ceramics (1-x)NaNbO3-xBi0.5Li0.5TiO3 have been fabricated by an ordinary sintering technique,and their electric properties and temperature characteristics have been studied. All the ceramics possess a perovskite structure with orthorhombic symmetry, indicating that (Bi0.5Li0.5)TiO3 diffuses into NaNbO3 lattices to form a new solid solution. A low (Bi0.5Li0.5)TiO3 doping level transforms the NaNbO3ceramics from antiferroelectric to ferroelectric. The ceramics with x ≤ 0.075 are normal ferroelectric, and the ferroelectric-paraelectric phase become diffusives with the doping level of Bi0.5Li0.5TiO3 increasing. As x increases, the Curie temperature of the ceramics decreases linearly, while the relative permittivity εr increases. 0.925NaNbO3e0.075(Bi0.5Li0.5)TiO3 ceramic exhibits the relatively large piezoelectric constant (d33 = 58 pC/N), high Curie temperature (TC = 228 ℃) and good temperature stability, suggesting that the ceramics are one of new possible candidates for lead-free piezoelectric materials. Lead-free ceramics (1-x)NaNbO3-xBi0.5Li0.5TiO3 have been fabricated by an ordinary sintering technique,and their electric properties and temperature characteristics have been studied. All the ceramics possess a perovskite structure with orthorhombic symmetry, indicating that (Bi0.5Li0.5)TiO3 diffuses into NaNbO3 lattices to form a new solid solution. A low (Bi0.5Li0.5)TiO3 doping level transforms the NaNbO3ceramics from antiferroelectric to ferroelectric. The ceramics with x ≤ 0.075 are normal ferroelectric, and the ferroelectric-paraelectric phase become diffusives with the doping level of Bi0.5Li0.5TiO3 increasing. As x increases, the Curie temperature of the ceramics decreases linearly, while the relative permittivity εr increases. 0.925NaNbO3e0.075(Bi0.5Li0.5)TiO3 ceramic exhibits the relatively large piezoelectric constant (d33 = 58 pC/N), high Curie temperature (TC = 228 ℃) and good temperature stability, suggesting that the ceramics are one of new possible candidates for lead-free piezoelectric materials.

The nonlinear absorption of graphene oxide water solution in femtosecond regime

Lingling Ran,Zhijun Chai,Yachen Gao,Wenzhi Wu,Qing Chang,Degui Kong 한국물리학회 2016 Current Applied Physics Vol.16 No.9

The nonlinear absorption properties of graphene oxide water solution were investigated with femtosecond pulses using Z-scan and pump-probe techniques at 800 nm wavelength. The researching results indicated that the nonlinear absorption of graphene oxide water solution include three parts: twophoton absorption of bound electrons from valence band, excited state absorption of electrons from the low energy state in conduction band and the excited state absorption of electrons from the bottom of conduction band. By theoretically fitting the experimental results, we got the two-photon absorption coefficient about b ¼ 3 1014 m/W, and the two excited state absorption cross section in the order of 1020 m2 and 1021 m2 respectively. In addition, the excited state lifetime of electron on the low energy state of conduction band was obtained. The investigation indicated that graphene oxide water solution is a good nonlinear optical material.

AITC induces MRP1 expression by protecting against CS/CSE-mediated DJ-1 protein degradation via activation of the DJ-1/Nrf2 axis

Lingling Xu,Jie Wu,Nini Li,Chengjun Jiang,Yan Guo,Peng Cao,Dianlei Wang 대한생리학회-대한약리학회 2020 The Korean Journal of Physiology & Pharmacology Vol.24 No.6

The present study aimed to examine the effect of allyl isothiocyanate (AITC) on chronic obstructive pulmonary disease and to investigate whether upregulation of multidrug resistance-associated protein 1 (MRP1) associated with the activation of the PARK7 (DJ-1)/nuclear factor erythroid 2-related factor 2 (Nrf2) axis. Lung function indexes and histopathological changes in mice were assessed by lung function detection and H&E staining. The expression levels of Nrf2, MRP1, heme oxygenase-1 (HO-1), and DJ-1 were determined by immunohistochemistry, Western blotting and reverse transcription-quantitative polymerase chain reaction. Next, the expression of DJ-1 in human bronchial epithelial (16HBE) cells was silenced by siRNA, and the effect of DJ-1 expression level on cigarette smoke extract (CSE)-stimulated protein degradation and AITC-induced protein expression was examined. The expression of DJ-1, Nrf2, HO-1, and MRP1 was significantly decreased in the wild type model group, while the expression of each protein was significantly increased after administration of AITC. Silencing the expression of DJ-1 in 16HBE cells accelerated CSE-induced protein degradation, and significantly attenuated the AITC-induced mRNA and protein expression of Nrf2 and MRP1. The present study describes a novel mechanism by which AITC induces MRP1 expression by protecting against CS/CSEmediated DJ-1 protein degradation via activation of the DJ-1/Nrf2 axis.

Effect of additives on structure and corrosion resistance of ceramic coatings on Mg–Li alloy by micro-arc oxidation

Shi Lingling,Xu Yongjun,Li Kang,Yao Zhongping,Wu Songquan 한국물리학회 2010 Current Applied Physics Vol.10 No.3

In order to improve the corrosion resistance of ceramic coatings formed on Mg–5mass%Li substrate by micro-arc oxidation (MAO) method, two kinds of additives (Na2B4O7 and EDTA) were doped in Na2SiO3–Na3PO4 solution system. The surface and cross-section morphology feature, phase composition and elemental composition were examined by SEM, XRD and EDX, respectively. Corrosion resistance of ceramic coating was tested by electrochemical methods. It was revealed that all coatings were composed of MgO and Mg2SiO4, and had porous surface structure. Doping of additives had little effect on the elemental composition, while it influenced the morphological feature of the coating. The results of electrochemical tests showed that the coatings prepared in the solutions with additive had good corrosion resistance. The addition of EDTA to the solution made coatings thinner and more uniform which resulted in better general corrosion resistance. The addition of Na2B4O7 to the solution made coatings much thicker and compacter, which improved the pitting corrosion resistance.

Remote sensing of early-stage green tide in the Yellow Sea for floating-macroalgae collecting campaign

Xing, Qianguo,Wu, Lingling,Tian, Liqiao,Cui, Tingwei,Li, Lin,Kong, Fanzhou,Gao, Xuelu,Wu, Mengquan Elsevier 2018 Marine pollution bulletin Vol.133 No.-

<P><B>Abstract</B></P> <P>The world's largest green tide originated from the Jiangsu Shoal of the Yellow Sea was due to fast reproduction of floating green macroalgae (<I>Ulva prolifera</I>). It brought significant impacts on marine environment and ecosystem in the Yellow Sea. In this study, we examined the expansion of green tide from the Jiangsu Shoal during the period from 29 April to 25 June 2016. Using high-resolution satellite images, we revealed a declined growth rate during the northward drifting of early-stage green tide for the first time, i.e., the green tide had higher growth rate (up to 25% per day) in the turbid waters of the Jiangsu Shoal in May and a lower growth rate (low to 3% per day) in the relatively clear waters in the middle of the western Yellow Sea in June, which suggests that water clarity might not be the key factor controlling the growth rate of the floating macroalgae in the surface waters under natural conditions. The high growth rate led to shortened time windows for controlling the green tide by employing macroalgae collecting campaigns at the initial sites of the green tide, which was no more than 14 days in the 2016 case.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Using high-resolution satellite image for detecting early-stage green tide </LI> <LI> Found changing growth rate of green tide </LI> <LI> Assessed the countermeasure of collecting floating-macroalgae at the initial sites </LI> </UL> </P>

Adaptive Practical Tracking Control for a Class of Uncertain Flexible Joint Robots with Variable Stiffness Actuators

Jian Li,Lingling Zhu,Zhaojing Wu 제어·로봇·시스템학회 2023 International Journal of Control, Automation, and Vol.21 No.2

This paper is devoted to the tracking control of a class of uncertain flexible joint robots with variable stiffness actuators (VSAs). Compared with the related literature, more serious system uncertainties are allowed since the disturbances exist in all the three subsystems but only in one or two subsystems in those of the related literature. Moreover, more wide class of reference signals can be tracked since which are only first order continuously differentiable rather than higher order (more than two) continuously differentiable in the related literature. To solve the control problem, a novel adaptive practical tracking control design scheme is proposed by skillfully incorporating the adaptive dynamic compensation technique into the vectorial backstepping framework. Then, adaptive tracking controllers are explicitly designed which ensure that all the states of the resulting closed-loop system are bounded while the system outputs practically track the reference signals, i.e., the tracking errors arrive and then stay at an arbitrary neighborhood of the origin after some time. It is worth strengthening that the proposed controllers do not require the measurements of the derivatives for reference signals but those of the related literature must do, and hence is much more applicable. Finally, simulation is provided to validate the proposed theoretical results.

Infl uence of Column Supports on Seismic Performance of K8 Single-Layer Spherical Reticulated Domes with Friction Pendulum Bearings

Dewen Kong,Lingling Wang,Liao Wu,Yuxia Zhang 한국강구조학회 2019 International Journal of Steel Structures Vol.19 No.3

The friction pendulum bearing (FPB) has been proved to be good isolation equipment, and the friction pendulum bearings were applied to K8 single-layer reticulated domes which span was 80 m. By using the vibration reduction analysis method based on the refi ne element models of FPBs, the seismic performance of the single-layer spherical reticulated domes with FPBs was studied and the infl uence of the column height and radius of section was discussed on the seismic performance of structures under the horizontal earthquakes. The results indicate that, with the increasing of height and radius of section of the supporting column, the vibration reduction eff ect of column supporting K8 single-layer reticulated domes with FPBs is enhanced fi rst and then weakened. Under the horizontal earthquakes, the resonance phenomenon of K8 single-layer reticulated domes with column supports could be eff ectively avoided by the use of FPBs. For the cylindrical column supporting K8 single-layer reticulated domes with FPBs, compared with the corresponding hinge support structure, the vibration reduction eff ect of column support structure with FPBs which column height is 8 m is better when the column section radius is 0.50 m. However, the optimal column section radii are between 0.60 and 0.70 m when the column height is 10 m.

Dynamic Economic Dispatch for Microgrid Based on the Chance-Constrained Programming

Daizheng Huang,Lingling Xie,Zhihui Wu 대한전기학회 2017 Journal of Electrical Engineering & Technology Vol.12 No.3

The power of controlled generators in microgrids randomly fluctuate because of the stochastic volatility of the outputs of photovoltaic systems and wind turbines as well as the load demands. To address and dispatch these stochastic factors for daily operations, a dynamic economic dispatch model with the goal of minimizing the generation cost is established via chance-constrained programming. A Monte Carlo simulation combined with particle swarm optimization algorithm is employed to optimize the model. The simulation results show that both the objective function and constraint condition have been tightened and that the operation costs have increased. A higher stability of the system corresponds to the higher operation costs of controlled generators. These operation costs also increase along with the confidence levels for the objective function and constraints.

Characterization of eight Bacillus thuringiensis isolates originated from fecal samples of Fuzhou Zoo and Fuzhou Panda Center

ChangbiaoWu,Lili Wu,Lingling Zhang,Ivan Gelbi,Lei Xu,Xiong Guana 한국응용곤충학회 2014 Journal of Asia-Pacific Entomology Vol.17 No.3

In eight fecal samples of 5 herbivorous animals from Fuzhou Zoo and Fuzhou Panda Center were found eightBacillus thuringiensis isolates. Obtained isolates were characterized by crystal microscopy, cry identification,and assay against the development of Eimeria tenella oocyst in chicken embryo. Bt WCB1, WCB2, WCB3 andWCB8, originated from horse, spotted deer, giant panda and lesser panda, respectively, all exhibited bipyramidaland cuboidal crystal and harbored the same cry genes, which were cry1Cb, cry1Db, cry1Fa, cry1Ib and cry2Ab. WCB7, a Bt isolate with bipyramidal crystal from zebra, showed a different cry pattern, cry1Cb, cry1Db, cry1Faand cry1Ia. BtWCB6, the third Bt isolate fromgiant panda, also contained bipyramidal crystal, however, harboredcry1Ib only. It was noted that Bt isolate WCB5 contained cuboidal crystal and harbored an unknown cry3 gene. It was very interesting that no cry genes were detected from Bt isolate WCB4 with dot-like crystal. Parasporalcrystal proteins of WCB3, WCB4 and WCB7 obviously inhibited the development of E. tenella oocyst in chickenembryo.

Experiment on the Behavior of a Self-Anchored Suspension and Cable-Stayed Hybrid Bridge during Structural Transformation

Yu Zhao,Yongjun Zhou,Lingling Wu,Changchang Li,Zhongguo John Ma 대한토목학회 2020 KSCE JOURNAL OF CIVIL ENGINEERING Vol.24 No.6

The Longgang Bridge in Shaanxi, China, is a complex continuous hybrid structure composed of two cable-stayed self-anchored suspension parts and one single-pylon cable-stayed part. A 1:20-scaled model was established due to the effect of multiple structural transformation, frequent internal force changes during the construction process, and differences between actual material parameters and theoretical calculation parameters. In this paper, the design, materials, counterweight, experimental instrumentation, and construction stages of the scaled model are introduced. Based on the experimental data, the nonlinear behavior of the self-anchored suspension and cable-stayed hybrid bridge during the structural transformation of the construction process is systematically and comprehensively studied. The evolutions of the hanger force and stayed cable force, the variation in the subcable and back-cable forces, the displacement characteristics of the suspension cable and the deflection of the stiffened girder are analyzed, and the relationships among these variables in different states of the structural system are discussed. This paper will serve as a technical reference for the construction of similar bridges in the future.