Donghua University

About: Donghua University is a education organization based out in Shanghai, China. It is known for research contribution in the topics: Fiber & Nanofiber. The organization has 21155 authors who have published 21841 publications receiving 393091 citations. The organization is also known as: Dōnghuá Dàxué & China Textile University.

Max-Min Approach to Nonlinear Oscillators

Abstract: This paper suggests a novel method called max-min method. Maximal and minimal solution thresholds of a nonlinear problem can be easily found, and an approximate solution of the nonlinear equation can be easily deduced using He Chengtian’s interpolation, which has millennia history. Application of the method to nonlinear oscillators is systematically illustrated, illustrating examples show the present technology is very convenient and effective.

High-capacity rechargeable batteries based on deeply cyclable lithium metal anodes.

Abstract: Discovering new chemistry and materials to enable rechargeable batteries with higher capacity and energy density is of paramount importance. While Li metal is the ultimate choice of a battery anode, its low efficiency is still yet to be overcome. Many strategies have been developed to improve the reversibility and cycle life of Li metal electrodes. However, almost all of the results are limited to shallow cycling conditions (e.g., 1 mAh cm −2 ) and thus inefficient utilization ( −2 with average Coulombic efficiency >98% in a commercial LiPF 6 /carbonate electrolyte. The high performance is enabled by slow release of LiNO 3 into the electrolyte and its subsequent decomposition to form a Li 3 N and lithium oxynitrides (LiN x O y )-containing protective layer which renders reversible, dendrite-free, and highly dense Li metal deposition. Using the developed Li metal electrodes, we construct a Li-MoS 3 full cell with the anode and cathode materials in a close-to-stoichiometric amount ratio. In terms of both capacity and energy, normalized to either the electrode area or the total mass of the electrode materials, our cell significantly outperforms other laboratory-scale battery cells as well as the state-of-the-art Li ion batteries on the market.

Antimicrobial electrospun nanofibers of cellulose acetate and polyester urethane composite for wound dressing.

Abstract: In this study, a series of nanofibrous membranes were prepared from cellulose acetate (CA) and polyester ure- thane (PEU) using coelectrospinning or blend-electrospin- ning. The drug release, in vitro antimicrobial activity and in vivo wound healing performance of the nanofiber mem- branes were evaluated for use as wound dressings. To pre- vent common clinical infections, an antimicrobial agent, polyhexamethylene biguanide (PHMB) was incorporated into the electrospun fibers. The presence of CA in the nano- fiber membrane improved its hydrophilicity and permeabil- ity to air and moisture. CA fibers became slightly swollen upon contacting with liquid phase. CA not only increased the liquid uptake but also created a moist environment for the wound, which accelerated wound recovery. PHMB release dynamics of the membranes was controlled by the structure and component ratios of the membranes. The lower ratio of CA: PEU helped to preserve the physical and thermal properties of the membranes, and also reduced the burst release effectively and slowed down diffusion of PHMB during in vitro tests. The controlled-diffusion mem- branes exerted long-term antimicrobial effect for wound

Vanillin-Based Epoxy Vitrimer with High Performance and Closed-Loop Recyclability

Abstract: It is of great importance to develop epoxy vitrimers with the combination of high performance and versatile recyclability. Herein, two imine-containing hardeners were synthesized from bio-based vanillin and petroleum-based p-hydroxy benzaldehyde. The epoxy resins cured by these two hardeners show high Tg (>120 °C), tensile strength (>60 MPa), Young’s modulus (>2500 MPa), and good solvent resistance. Owing to the incorporation of imine dynamic covalent bond, the cured epoxy resins are reprocessable and degradable. Notably, the chemical degradation products can be reused to prepare new epoxy resins, thus achieving a closed-loop recycling process. Both the reprocessed and chemically recycled epoxy resins exhibit high-percentage retention of thermal and mechanical properties. Finally, this study demonstrates that the epoxy resin cured by the vanillin-based hardener shows comparable thermal, mechanical, and recycling properties compared with the epoxy resin cured by the petroleum-based counterpart.

On Nonlinear $H_{\infty }$ Filtering for Discrete-Time Stochastic Systems With Missing Measurements

Abstract: In this paper, the H infin filtering problem is investigated for a general class of nonlinear discrete-time stochastic systems with missing measurements. The system under study is not only corrupted by state-dependent white noises but also disturbed by exogenous inputs. The measurement output contains randomly missing data that is modeled by a Bernoulli distributed white sequence with a known conditional probability. A filter of very general form is first designed such that the filtering process is stochastically stable and the filtering error satisfies H infin performance constraint for all admissible missing observations and nonzero exogenous disturbances under the zero-initial condition. The existence conditions of the desired filter are described in terms of a second-order nonlinear inequality. Such an inequality can be decoupled into some auxiliary ones that can be solved independently by taking special form of the Lyapunov functionals. As a consequence, a linear time-invariant filter design problem is discussed for the benefit of practical applications, and some simplified conditions are obtained. Finally, two numerical simulation examples are given to illustrate the main results of this paper.