Online Adaptive Optimal Tracking Control of Nonholonomic Mobile Robot

Kai Wang,Yingmin Jia,Junping Du,Jun Zhang 제어로봇시스템학회 2012 제어로봇시스템학회 국제학술대회 논문집 Vol.2012 No.10

A velocity control law is developed for the kinematic steering system of nonholonomic mobile robot to track a reference trajectory not only to make the posture error asymptotically stable but also considered optimality based on a pre-defined cost function. In order to make the cost function finite, we transformed the tracking problem into a regulation problem by redefining system states and inputs. The proposed online and forward-in-time policy iteration (PI) algorithm based on approximate dynamic programming (ADP) to solve the continuous-time(CT) optimal control problem with infinite horizon cost by solving of Hamilton-Jacobi-Bellman (HJB) equation. This method learns online in real-time to approximate the cost function by using a single neural networks (NNs), and then the near optimal control policy can be computed directly according to the cost function, which removes the action network appearing in the ordinary ADP methods. Simulation results are provided to demonstrate the effectiveness of the proposed approach.

Applications of Heavy Ion Irradiation in Photonic Crystal Research

Ziqiang Zhao,Yingmin Liu,Yan Chen,Ding Lan,Yuren Wang 한국물리학회 2009 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.55 No.6

Photonic crystals (PC) have received extensive attention for the photonic band gap (PBG). The polystyrene (PS) particles bottom-up approach is a productive method for photonic crystal manufacture, this kind of photonic crystals having an unique PBG that depends on the particle’s shape, sizes and defects. Heavy ion irradiation is a very useful method to induce defects in PC and change the shapes of the particles to tune the PBG. MeV heavy ion irradiation leads to an anisotropic deformation of the particles from spherical to ellipsoidal, the aspect ratio of which can be precisely controlled by using the ion energy and flux. Sub-micrometer PS particles were deposited on a Cu substrate and were irradiated at 230 K by using heavy ion energy and fluence in the range from 2 to 10 MeV and 1 × 1014 cm−2 to 1 × 1015 cm−2, respectively. Photonic crystals (PC) have received extensive attention for the photonic band gap (PBG). The polystyrene (PS) particles bottom-up approach is a productive method for photonic crystal manufacture, this kind of photonic crystals having an unique PBG that depends on the particle’s shape, sizes and defects. Heavy ion irradiation is a very useful method to induce defects in PC and change the shapes of the particles to tune the PBG. MeV heavy ion irradiation leads to an anisotropic deformation of the particles from spherical to ellipsoidal, the aspect ratio of which can be precisely controlled by using the ion energy and flux. Sub-micrometer PS particles were deposited on a Cu substrate and were irradiated at 230 K by using heavy ion energy and fluence in the range from 2 to 10 MeV and 1 × 1014 cm−2 to 1 × 1015 cm−2, respectively.

Fabrication and Soft Magnetic Properties of Fe–B–Si–Zr/Hf–Cu Nanocrystalline Alloys with High Glass-Forming Ability

Yaoxiang Geng,Yingmin Wang,Yuxin Wang,Zhijie Zhang,Hongbo Ju,Lihua Yu,Junhua Xu 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.11

The effects of minor alloying addition of Cu on the glass-forming ability and crystallization process of Fe71.7−xB16.7Si8.3Zr3.3Cuxand Fe72.5−xB16.7Si8.3Hf2.5Cux (x = 0, 0.3, 0.7, 1.0 and 1.3; at%) alloys were investigated. It was found that the critical glassformation size of rod samples gradually decreased from 2.5 to 1 mm with increasing Cu content in these alloys. Single α-Fe phase nanocrystalline alloys were obtained after isothermal annealing the Fe–B–Si–Zr/Hf–Cu glassy alloys containing0.7–1.0 at% Cu. The Fe71B16.7Si8.3Zr3.3Cu0.7alloy exhibited good soft magnetic properties with a high saturation magnetization(~ 1.22 T) and a low coercive force (~ 0.6 A/m) after annealing at 853 K for 10 min due to the precipitation of α-Fenanoparticles of 8 nm size in the glassy matrix. The structural evolution on annealing and the variation tendencies against Cucontent of the glass transition temperature, thermal stability and glass-forming ability of the Fe–B–Si–Zr/Hf–Cu amorphousalloys were discussed using a dual-cluster local structure model.

Rapid Melt Polycondensation of L-Lactic Acid under Microwave Irradiation

Shu Jing,Wang Peng,Zhang Yingmin,Mi Xiaojuan 한국고분자학회 2006 Macromolecular Research Vol.14 No.6

Irigenin exerts anticancer effects on human liver cancer cells via induction of mitochondrial apoptosis and cell cycle arrest

Xu Wanggang,Kuang Yingmin,Wang Dan,Li Zhen,Xia Renpin 한국응용생명화학회 2021 Applied Biological Chemistry (Appl Biol Chem) Vol.64 No.1

Irigenin has been reported to exhibit remarkable anticancer effects against several human cancers. Nonetheless, the anticancer effects of irigenin against the human liver cancer cells are still largely unexplored. Consistently, this study was designed to evaluate the anticancer effects of irigenin against human liver cancer cells and to unveil the underlying molecular mechanisms. The results showed that irigenin significantly (p < 0.05) inhibited the growth of the human HepG2 and SNU-182 liver cancer cells with an IC50 value of 14 μM. Nonetheless, the cytotoxic effects of irigenin against the normal THLE-2 cells were comparatively lower as evident from the IC50 of 120 μM. The AO/EB and DAPI staining showed that irigenin induces apoptosis in the human liver cancer cells. Annexin V/PI staining assay revealed a significant (p < 0.05) increase in the percentage of apoptotic HepG2 and SNU-182 liver cancer cells upon treatment with irigenin. It was found that the number of apoptotic HepG2 and SNU-182 cells enhanced from 2.3 to 41.75% and 1.16 to 51.9% at IC50, respectively. Western blot showed a considerable increase in Bax and decrease in the Bcl-2 expression upon irigenin treatment further confirming the induction of apoptosis. Flow cytometric analysis revealed that irigenin also induces G2/M cell cycle arrest of HepG2 and SNU-182 cells. The percentage of G2/M phase HepG2 and SNU-182 cells increased from 17.92 to 34.35% and 23.97 to 38.23% at IC50, respectively This was also accompanied by decrease in the expression of CDK1 and Cyclin-B in HepG2 and SNU-182 cells. Taken together, the results of the present study suggest that irigenin inhibits the growth of the human liver cancer cells via induction of apoptosis and cell cycle arrest. These results point towards the potential of irigenin as a lead for the development of chemotherapy for liver cancer.

Prediction of Cellulose Crystallinity in Liquid Phase Using CBM-GFP Probe

Xiaoyu Guo,Fan Yang,Huixue Liu,Yingmin Hou,Yafang Wang,Jie Sun,Xiaoyi Chen,Yanan Liu,Xianzhen Li 한국고분자학회 2019 Macromolecular Research Vol.27 No.4

Carbohydrate-binding modules (CBMs) have been developed to investigate the presence of crystalline and amorphous regions of cellulose. However, systematic and quantitative assessment of cellulose crystallinity using such non-hydrolytic fusion proteins in liquid phase has not been reported. In this work, cellulose directed CBM probes containing a green fluorescent protein (GFP) were constructed and named CG17, CG28, and CG2a. The probe binding condition was determined as incubating 30 μg/mL probes in 10 mM phosphate buffer at 30oC for 60 min. Under the optimized condition, the linear correlations between CBM probe binding capability and X-ray diffraction (XRD) crystallinity were well established. Using linear regression equations, the crystallinity of several cellulosic materials was well calculated. Amorphous component and cellulosic surface area probably had a less effect on binding capability of CG2a than that of CG17 and CG28. Therefore, crystalline-region specific probe CG2a should be an efficient tool for interpreting the crystallinity of cellulosic materials.

Preparation of Monodisperse Colloidal ZnO Nanoparticles and Their Optical Properties

Chong Yang,Limei Tang,Qingsong Li,Ailing Bai,Yanqiu Wang,Yingmin Yu 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2015 NANO Vol.10 No.5

Monodisperse colloidal zinc oxide (ZnO) nanospheres with a narrow size distribution were synthesized via a developed two-stage solution method. We controlled the size of the as-synthesized ZnO nanoparticles by varying the amount of ZnO/ethanol suspension added. Dynamic light scattering (DLS) and transmission electron microscopy (TEM) revealed that the diameter of the as-synthesized ZnO nanoparticles was in the range of 60 – 140 nm with a polydispersity index less than 5%. On high-resolution TEM images, we clearly observed that the ZnO nanospheres were actually composed of tiny ZnO subunits, several nanometers in size. Powder X-ray diffraction and TEM-selected area electron diffraction analysis showed that the spheres consisted of polycrystalline nanoparticles. The size of the subunits, which was confirmed by ultraviolet (UV)-visible spectroscopy, increased as the amount of ZnO/ethanol suspension added was decreased. A UV emission at about 374 nm was observed, and this emission of ZnO nanoparticles is found to depend on particle size due to the confinement effect. A red emission at about 651 nm, which has been reported for undoped ZnO, appeared due to the excess oxygen on the particles from O – H or C=O groups. The intensity of the red emission increased as the relative oxygen content increased. The formation mechanism of such ZnO nanospheres was also considered.