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.

Free-standing three-dimensional graphene and polyaniline nanowire arrays hybrid foams for high-performance flexible and lightweight supercapacitors

Abstract: Free-standing three-dimensional hierarchical porous reduced graphene oxide foam (RGO-F) was first fabricated by a “dipping and dry” method using nickel foam as a template. Three-dimensional (3D) RGO-F with high conductivity provides large porosity compared to conventional graphene films. Polyaniline (PANI) nanowire arrays aligned on the foam (RGO-F/PANI) were synthesized by in situ polymerization. A symmetric supercapacitor with high energy and power densities was fabricated using a RGO-F/PANI electrode. The highly flexible RGO-F/PANI foam can directly serve as an electrode with no binders or conductive additives. Owing to the well-ordered porous structure and high electrochemical performance of the RGO-F/PANI composite, the symmetric device exhibits high specific capacitance (790 F g−1) and volumetric capacitance (205.4 F cm−3), and it shows a maximum energy density and power density of 17.6 W h kg−1 and 98 kW kg−1. Moreover, the device possesses an excellent cycle life with 80% capacitance retention after 5000 cycles.

Robust finite-horizon filtering for stochastic systems with missing measurements

Abstract: In this letter, we consider the robust finite-horizon filtering problem for a class of discrete time-varying systems with missing measurements and norm-bounded parameter uncertainties. The missing measurements are described by a binary switching sequence satisfying a conditional probability distribution. An upper bound for the state estimation error variance is first derived for all possible missing observations and all admissible parameter uncertainties. Then, a robust filter is designed, guaranteeing that the variance of the state estimation error is not more than the prescribed upper bound. It is shown that the desired filter can be obtained in terms of the solutions to two discrete Riccati difference equations, which are of a form suitable for recursive computation in online applications. A simulation example is presented to show the effectiveness of the proposed approach by comparing to the traditional Kalman filtering method.

Fabrication of drug‐loaded electrospun aligned fibrous threads for suture applications

Abstract: In this work, drug-loaded fibers and threads were successfully fabricated by combining electrospinning with aligned fibers collection Two different electrospinning processes, that is, blend and coaxial electrospinning, to incorporate a model drug tetracycline hydrochloride (TCH) into poly(L-lactic acid) (PLLA) fibers have been used and compared with each other The resulting composite ultrafine fibers and threads were characterized through scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, differential scanning calorimetry, and tensile testing It has been shown that average diameters of the fibers made from the same polymer concentration depended on the processing method The blend TCH/PLLA fibers showed the smallest fiber diameter, whereas neat PLLA fibers and core-shell TCH-PLLA fibers showed a larger proximal average diameter Higher rotating speed of a wheel collector is helpful for obtaining better-aligned fibers Both the polymer and the drug in the electrospun fibers have poor crystalline property In vitro release study indicated that threads made from the core-shell fibers could suppress the initial burst release and provide a sustained drug release useful for the release of growth factor or other therapeutic drugs On the other hand, the threads from the blend fibers produced a large initial burst release that may be used to prevent bacteria infection A combination of these results suggests that electrospinning technique provides a novel way to fabricate medical agents-loaded fibrous threads for tissue suturing and tissue regeneration applications

Underwater Communication and Optical Camouflage Ionogels

Abstract: Marine animals, such as leptocephalus and jellyfish, can sense external stimuli and achieve optical camouflage in the aquatic environment. Fabricating an intelligent soft sensor that can mimic the capabilities of transparent marine animals and function underwater can enable transformative applications in various novel fields. However, previously reported soft sensors struggle to meet the requirements of adhesion, self-healing ability, optical transparency, and stable conductivity in the aquatic environment. Herein, high-performance ionogels by virtue of ion-dipole and ion-ion interactions between fluorine-rich poly(ionic liquid) and ionic liquid are designed. The hydrophobic dynamic viscoelastic networks provide excellent properties for ionogels, including optical transparency, adjustable mechanical properties, underwater self-healing ability, underwater adhesiveness, conductivity, and 3D printability. A mechanically compliant and visually invisible underwater soft sensor based on ionogel is developed. This sensor can achieve optical camouflage, human-body-motion detection, and barrier-free communication in the aquatic environment. A novel contactless sensing mechanism based on changing the electron transfer pathway is proposed. Several interesting functions, such as detection of water environment changes, recognition of objects, delivery of information, and even identification of human standing posture can be realized. Importantly, the ionogel sensor can avoid fatigue and physical damage in the sensing process.