Property Studies of Optical Waveguide Formed by keV He-Ion Implanted into a Nd:CNGG Crystal

Chunxiao Yu,Jin-Hua Zhao,Huai-Jin Zhang,Xue-Lin Wang 한국물리학회 2009 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.55 No.6

A planar optical waveguide was formed in a neodymium-doped calcium niobium gallium garnet (Nd:CNGG) crystal by using 500-keV He-ion implantation with a dose of 2 × 1016 ions/cm2 at room temperature. The dark modes were observed by using a prism coupling method, and the refractive index profile was reconstructed using a reflectivity calculation method (RCM). The SRIM2006 code (stopping and range of ions in matters, code 2006) was used to simulate the damage profile in the ion-implanted sample. The photoluminescence spectra of the samples showed fairly good potential for used as a laser waveguide.

Barrier Lyapunov Functions-based Adaptive Control for Nonlinear Purefeedback Systems with Time-varying Full State Constraints

Chunxiao Wang,Yu-Qiang Wu,Jiang-Bo Yu 제어·로봇·시스템학회 2017 International Journal of Control, Automation, and Vol.15 No.6

This paper studies the problem of controller design for pure-feedback nonlinear systems with asymmetrictime-varying full state constraints. The mean value theorem is employed to transform a pure-feedback system intoa strict-feedback structure with non-affine terms. For the transformed system, a time-varying asymmetric BarrierLyapunov Function (ABLF) with the error variables is employed to ensure the time-varying constraints satisfaction. By allowing the barriers to vary with the desired trajectory in time, the initial condition requirements are relaxedefficiently. The presented control scheme can guarantee that all signals in the closed-loop system are ultimatelybounded. It is also proved that the tracking error converges to an adjustable neighborhood of the origin even in thepresence of disturbance. The performance of the ABLF-based control are illustrated through two examples.

Experimental and numerical simulation investigation on vortex-induced vibration test system based on bare fiber Bragg grating sensor technology for vertical riser

Wang Chunxiao,Wang Yu,Liu Yu,Li Peng,Zhang Xiantang,Wang Fei 대한조선학회 2021 International Journal of Naval Architecture and Oc Vol.13 No.1

The Vortex-Induced Vibration (VIV) test system on deepwater riser based on Bare Fiber Bragg Grating (BFBG) sensor technology was designed. Meanwhile, a riser VIV response numerical model was established based on the work-energy principle. The results show that the first-order vibration frequency dominates the vibration of the riser, and as the velocity increases, the dominant frequency of the riser gradually increases under the effect of different top tensions. At the same velocity, as the top tension increases step by step, the dominant frequency and fatigue damage at the same position along the axial length of the riser both gradually decreases. The model test and numerical simulation show a relatively consistent change, maintaining a high degree of agreement. The process control system based on BFBG of model test has excellent performance, and FBG sensors have great advantages in VIV test of a vertical riser in water.

Barrier Lyapunov Function Based Adaptive Cross Backstepping Control for Nonlinear Systems with Time-varying Partial State Constraints

Chunxiao Wang,Lu Qi,Jia-yun Liu,Jia-li Yu 제어·로봇·시스템학회 2020 International Journal of Control, Automation, and Vol.18 No.7

This paper focuses on an adaptive cross-backstepping control for a class of nonstrict-feedback nonlinear systems affected by time-varying partial state constraints. The nonstrict-feedback nonlinear systems considered in this paper are divided into two strict-feedback nonlinear subsystems. One constrained subsystems and another unconstrained subsystems. In view of the normal backstepping method is only an effective method to control lowertriangular systems, cross-backstepping control is introduced which successfully solves the problem of alternatetime-varying state constraints. For the constrained subsystems, novel time-varying tan-type barrier Lyapunov function (TBLF) is employed in each step of backstepping design to guarantee the boundedness of the fictitious or actual state tracking errors. Besides, proper adaptive laws are designed for the upper bound of uncertain parameters, which successfully neutralize the influence of parametric uncertainties. Based on the stability analysis, it is concluded that the states of the closed-loop system maintain in the predefined time-varying compact sets and the output can be guaranteed to be as close to the desired trajectory as possible. The effectiveness of the proposed technique is illustrated by a constrained hyperchaotic system in two cases.

Self-collision Avoidance Trajectory Planning and Robust Control of a Dual-arm Space Robot

Yicheng Liu,Chunxiao Yu,Jingyuan Sheng,Tao Zhang 제어·로봇·시스템학회 2018 International Journal of Control, Automation, and Vol.16 No.6

This paper addresses robust trajectory tracking for a dual-arm 6-DOF (degree of freedom) space robot with self-collision avoidance. A trajectory planning method for self-collision avoidance is presented with the information of danger field between the manipulators. On this basis, the kinematics and dynamics models of the whole system are considered together to realize the tracking of the end effectors. Thus a robust decentralized control strategy is proposed based on signal compensation and back-stepping. In contrast to the existing researches, the proposed scheme ensures that the space robotic system can automatically avoid self-collision and displays good robust performance. The simulation results verify the effectiveness of the proposed approach.

Antifouling Hydrophilic Electrostatic Spinning PAN Membrane Based on Click Chemistry with High Efficiency Oil-water Separation

Baosheng Shen,Chunxiao Du,Wei Wang,Dan Yu 한국섬유공학회 2022 Fibers and polymers Vol.23 No.12

With the increasingly serious water pollution and human health problems caused by oily wastewater, the task ofdeveloping new and efficient oil-water separation materials is becoming urgent. Electrospun nanofiber membranes have beenapplied to this field due to their high porosity and uniform pore size, but the preparation and mechanism of hydrophilicnanofiber membranes, which can be used in the part of underwater oleophobicity still need to be explored. Herein, we firstlyprepare nanofiber membranes containing sulfhydryl groups on the surface by electrostatic spinning of polyacrylonitrile and γ-mercaptopropyltriethoxysilane together, which becomes active sites for the grafting of dimethyldiallylammonium chloridemonomers by thiol-ene click chemistry. The resulting modified membranes exhibited hydrophilicity in air and oleophobicityin water, and demonstrated good emulsion separation performance of extremely high permeation flux (742.6 L/(m2·h)),excellent separation efficiency (>96 %), as well as outstanding antifouling performance thanks to the existence of hydrationlayer on the membrane when underwater. In addition, the membranes can maintain stable hydrophilicity and underwateroleophobicity in complex environments, and display good acid and alkali resistance.

Partial-state Feedback Stabilization for a Class of Generalized Nonholonomic Systems with ISS Dynamic Uncertainties

Yan Zhao,Chunxiao Wang,Jiang-Bo Yu 제어·로봇·시스템학회 2018 International Journal of Control, Automation, and Vol.16 No.1

In this paper, the problem of global stabilization control via partial-state feedback is addressed for a class of uncertain nonholonomic systems with the disturbed virtual control directions. The investigated nonholonomic system has the input-to-state stable (ISS) dynamic uncertainties. The small gain theorem and the changing supply function technique are employed to derive a global stabilization controller. Additionally, we develop a switching control strategy in order to get around the smooth stabilization burden associated with nonholonomic systems. The simulation results illustrate the efficacy of the presented algorithm.

The Candidate Tumor Suppressor Gene SLC8A2 Inhibits Invasion, Angiogenesis and Growth of Glioblastoma

Qu, Mingqi,Yu, Ju,Liu, Hongyuan,Ren, Ying,Ma, Chunxiao,Bu, Xingyao,Lan, Qing Korean Society for Molecular and Cellular Biology 2017 Molecules and cells Vol.40 No.10

Glioblastoma is the most frequent and most aggressive brain tumor in adults. Solute carrier family 8 member 2 (SLC8A2) is only expressed in normal brain, but not present in other human normal tissues or in gliomas. Therefore, we hypothesized that SLC8A2 might be a glioma tumor suppressor gene and detected the role of SLC8A2 in glioblastoma and explored the underlying molecular mechanism. The glioblastoma U87MG cells stably transfected with the lentivirus plasmid containg SLC8A2 (U87MG-SLC8A2) and negative control (U87MG-NC) were constructed. In the present study, we found that the tumorigenicity of U87MG in nude mice was totally inhibited by SLC8A2. Overexpression of SLC8A2 had no effect on cell proliferation or cell cycle, but impaired the invasion and migration of U87MG cells, most likely through inactivating the extracellular signal-related kinases (ERK)1/2 signaling pathway, inhibiting the nuclear translocation and DNA binding activity of nuclear factor kappa B ($NF-{\kappa}B$), reducing the level of matrix metalloproteinases (MMPs) and urokinase-type plasminogen activator (uPA)-its receptor (uPAR) system (ERK1/2-$NF-{\kappa}B$-MMPs/uPA-uPAR), and altering the protein levels of epithelial to mesenchymal transitions (EMT)-associated proteins E-cardherin, vimentin and Snail. In addition, SLC8A2 inhibited the angiogenesis of U87MG cells, probably through combined inhibition of endothelium-dependent and endothelium-nondependent angiogenesis (vascular mimicry pattern). Totally, SLC8A2 serves as a tumor suppressor gene and inhibits invasion, angiogenesis and growth of glioblastoma.

p53 overexpression represses androgen-mediated induction ofNKX3.1 in a prostate cancer cell line

Anli Jiang,Chunxiao Yu,Pengju Zhang,Weiwen Chen,Wenwen Liu,Xiaoyan Hu,Jianye Zhang 생화학분자생물학회 2006 Experimental and molecular medicine Vol.38 No.6

Prostate cancer is a disease involving complicated multiple-gene alterations. Both NKX3.1 and p53 are related to prostate cancer and play crucial roles in prostate cancer progression. However, little is known about the relationships and interactions between p53 and NKX3.1 in prostate cancer. We found that NKX3.1 expression is down-regulated by over-expression of wild type (wt) p53 in prostate cancer LNCaP cells. NKX3.1 is down-regulated at both the mRNA and protein levels by p53 overexpression due to either transient transfection of exogenous p53 or induction of endogenous p53. p53 over-expression represses androgen-induced transactivation of NKX3.1 by inhibiting the promoter of the androgen acceptor (AR) gene and by blocking AR-DNA binding activity. In addition, transfection with the p21 expression vector (pPSA-p21) showed that p21 does not reduce NKX3.1 expression, indicating that NKX3.1 expression is not the result of nonspecific effects of cell growth arrest. Our results provide biochemical and cellular biologic evidence that NKX3.1 is down-regulated by p53 over-ex - pression in prostate cancer cells.

Water-soluble ginseng oligosaccharides protect against scopolamine-induced cognitive impairment by functioning as an antineuroinflammatory agent

Xu, Ting,Shen, Xiangfeng,Yu, Huali,Sun, Lili,Lin, Weihong,Zhang, Chunxiao The Korean Society of Ginseng 2016 Journal of Ginseng Research Vol.40 No.3

Background: Panax ginseng root is used in traditional oriental medicine for human health. Its main active components such as saponins and polysaccharides have been widely evaluated for treating diseases, but secondary active components such as oligosaccharides have been rarely studied. This study aimed to assess the impact of water-soluble ginseng oligosaccharides (WGOS), which were isolated from the warm-water extract of Panax ginseng root, on scopolamine-induced cognitive impairment in mice and its antineuroinflammatory mechanisms. Methods: We investigated the impact of WGOS on scopolamine-induced cognitive impairment in mice by using Morris water maze and novel object recognition task. We also analyzed the impact of WGOS on scopolamine-induced inflammatory response (e.g., the hyperexpression of proinflammatory cytokines IL-$1{\beta}$ and IL-6 and astrocyte activation) by quantitative real-time polymerase chain reaction and glial fibrillary acid protein (GFAP) immunohistochemical staining. Results: WGOS pretreatment protected against scopolamine-induced learning and memory deficits in the Morris water maze and in the novel object recognition task. Furthermore, WGOS pretreatment downregulated scopolamine-induced hyperexpression of proinflammatory cytokines interleukin (IL)-$1{\beta}$ and IL-6 mRNA and astrocyte activation in the hippocampus. These results indicate that WGOS can protect against scopolamine-induced alterations in learning and memory and inflammatory response. Conclusion: Our data suggest that WGOS may be beneficial as a medicine or functional food supplement to treat disorders with cognitive deficits and increased inflammation.