Yanshan University

About: Yanshan University is a education organization based out in Qinhuangdao, China. It is known for research contribution in the topics: Microstructure & Control theory. The organization has 19544 authors who have published 16904 publications receiving 184378 citations. The organization is also known as: Yānshān dàxué.

Discrete Time Geo/G/1 Queue with Multiple Adaptive Vacations

Abstract: This paper treats the discrete time Geometric/G/1 system with vacations. In this system, after serving all customers in the system, the server will take a random maximum number of vacations before returning to the service mode. The stochastic decomposition property of steady-state queue length and waiting time has been proven. The busy period, vacation mode period, and service mode period distributions are also derived. Several common vacation policies are special cases of the vacation policy presented in this study.

Water-Insoluble Photosensitizer Nanocolloids Stabilized by Supramolecular Interfacial Assembly towards Photodynamic Therapy.

Abstract: Nanoengineering of hydrophobic photosensitizers (PSs) is a promising approach for improved tumor delivery and enhanced photodynamic therapy (PDT) efficiency. A variety of delivery carriers have been developed for tumor delivery of PSs through the enhanced permeation and retention (EPR) effect. However, a high-performance PS delivery system with minimum use of carrier materials with excellent biocompatibility is highly appreciated. In this work, we utilized the spatiotemporal interfacial adhesion and assembly of supramolecular coordination to achieve the nanoengineering of water-insoluble photosensitizer Chlorin e6 (Ce6). The hydrophobic Ce6 nanoparticles are well stabilized in a aqueous medium by the interfacially-assembled film due to the coordination polymerization of tannic acid (TA) and ferric iron (Fe(III)). The resulting Ce6@TA-Fe(III) complex nanoparticles (referenced as Ce6@TA-Fe(III) NPs) significantly improves the drug loading content (~65%) and have an average size of 60 nm. The Ce6@TA-Fe(III) NPs are almost non-emissive as the aggregated states, but they can light up after intracellular internalization, which thus realizes low dark toxicity and excellent phototoxicity under laser irradiation. The Ce6@TA-Fe(III) NPs prolong blood circulation, promote tumor-selective accumulation of PSs, and enhanced antitumor efficacy in comparison to the free-carrier Ce6 in vivo evaluation.

Stabilization of T-S Fuzzy System With Time Delay Under Sampled-Data Control Using a New Looped-Functional

Abstract: This paper investigates the sampled-data stabilization problem for a Takagi–Sugeno (T-S) fuzzy system with time delay. By taking the information of states within the intervals from $t_{k}$ to $t$ and $t$ to $t_{k+1}$ into account, a new two-side delay-dependent looped-functional is introduced which can not only relax the monotonic constraint of Lyapunov–Krasovskii functional (LKF), but also make better use of the actual sampling pattern. Furthermore the sampled-data fuzzy controller is designed to contain both the present and delayed state information, thereby enhancing the control performance and design flexibility. Based on the novel augmented LKF and improved bounding technique, less conservative stability criteria are derived in the form of linear matrix inequalities. The superiority of proposed results is shown by two simulation examples.

Crashworthiness of different composite tubes by experiments and simulations

Abstract: Composite tubes show a good energy absorbing ability and they have great potential as energy absorbing components to replace traditional metal structures in automobiles, aircrafts and other transportation. This paper aims to investigate the impacts of geometrical parameters, including intermediate diameter, wall thickness and upper end diameter, on the specific energy absorption (SEA) of composite tubes, metal tubes, foam-filled tubes and hybrid tubes. The mechanical characteristics (axial compression response) of these tubes were numerically predicted by commercial finite element (FE) package LS-DYNA. Quasi-static axial compression tests were performed to determine failure parameters of glass fiber reinforced polymer (GFRP) used in this paper. Stress-strain curves of polyurethane foam and aluminum foam were also obtained by tests. Finite element models of hollow GFRP, aluminum and aluminum-FRP tubes and polyurethane foam-filled and aluminum foam-filled composite tubes were established respectively. Configurations of these numerical models include circular, square and tapered (5 different upper end diameters) tubes. In optimization part, structural parameters optimization was carried out by response surface method (RSM). Results review that in general, SEA of circular tubes increases with smaller diameter-thickness ratio. In comparison part, SEA of circular, square and tapered tubes were compared. Results show that changing upper end diameter of tubes has great impacts on their energy absorption capacity, but sensitivities of SEA to geometrical parameters and cross-section shapes differ depending on materials of tubes and foam filling.

Optical temperature sensing based on the near-infrared emissions from Nd³⁺/Yb³⁺ codoped CaWO₄.

Abstract: Under a 980 nm diode laser excitation, the near-infrared (NIR) emissions from Nd3+:4F7/2, 4F5/2, and 4F3/2 states in Nd3+/Yb3+ codoped CaWO4 powder were studied at temperatures ranging from 303 to 873 K. As the temperature increased, the NIR luminescence intensity was significantly enhanced and nearly 190-fold enhancement was achieved at 873 K compared with that at 303 K. By using the fluorescence intensity ratio technique, the thermometry behaviors through the NIR emissions were investigated. The results illustrate that the sensitivity and the accuracy achieved here are much higher than temperature sensors based on other rare earth ion doped materials.