Shuang Zheng

Bio: Shuang Zheng is an academic researcher from University of Texas at Austin. The author has contributed to research in topics: Hydraulic fracturing & Fracture (geology). The author has an hindex of 9, co-authored 33 publications receiving 226 citations. Previous affiliations of Shuang Zheng include China University of Petroleum.

One-step preparation of MoOx/ZnS/ZnO composite and its excellent performance in piezocatalytic degradation of Rhodamine B under ultrasonic vibration.

Abstract: This paper synthesized a new type of ternary piezoelectric catalyst MoOx/ZnS/ZnO (MZZ) by a one-step method. The catalytic degradation of Rhodamine B (RhB) solution (10 µg/g, pH = 7.0) shows that the composite catalyst has excellent piezoelectric catalytic activity under ultrasonic vibration (40 kHz). The piezoelectric degradation rate of the optimal sample reached 0.054 min−1, which was about 2.5 times that of pure ZnO. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman, transmission electron microscopy (TEM), scanning electron microscopy (SEM), and electrochemical impedance spectroscopy (EIS) technologies were used to analyze the structure, morphology, and interface charge transfer properties of the MZZ piezocatalysts. The results showed that the composite catalyst may have a core-shell structure. ZnS is coated on the surface of ZnO, while MoOx adheres to the surface of ZnS. This structure endowed MZZ larger specific surface area than ZnO, which benefits the RhB adsorption. More importantly, the formed heterojunction structure between ZnS and ZnO promotes the separation of positive and negative charges induced by the piezoelectric effect. MoOx species may act as a charge trap to further promote more carriers to participate in the reaction. In addition, MoOx may also be beneficial in adsorbing dyes. Active species capture experiments show that superoxide radicals and holes are the main active species in piezoelectric catalytic reactions on MZZ catalysts.

Integrating Reservoir Geomechanics with Multiple Fracture Propagation and Proppant Placement

Abstract: This paper presents the formulation and results from a coupled finite-volume (FV)/finite-area (FA) model for simulating the propagation of multiple hydraulically driven fractures in two and three dimensions at the wellbore and pad scale. The proposed method captures realistic representations of local heterogeneities, layering, fracture turning, poroelasticity, interactions with other fractures, and proppant transport. We account for competitive fluid and proppant distribution between multiple fractures from the wellbore. Details of the model formulation and its efficient numerical implementation are provided, along with numerical studies comparing the model with both analytical solutions and field results. The results demonstrate the effectiveness of the proposed method for the comprehensive modeling of hydraulically driven fractures in three dimensions at a pad scale.

Self-healing supramolecular hydrogels fabricated by cucurbit[8]uril-enhanced π-π interaction

Abstract: Novel self-healing supramolecular hydrogels have successfully been fabricated through reversible cucurbit[8]uril (CB[8])-enhanced π-π interaction. Naphthaline groups in the side chains of copolymers and CB[8] molecules are employed as cross-linkers to form 1:2 ternary complex by host-guest interaction. Furthermore, the dipole-dipole interaction between the polar carbonyl groups of CB[8] and quaternary ammonium cation also contributes to the formation of self-healing property. It is found that the molar ratio of CB[8] to naphthaline units has a great influence on its self-healing property. This work represents a facile approach for fabricating cucurbituril-based self-healing supramolecular hydrogels, which can be potentially applied in several fields.

Self-Healable Gels for Use in Wearable Devices

Abstract: Self-healing gels, which are able to restore their original shape/condition after damage, have recently attracted considerable interest. The present review provides an update on the current status of self-healing gels for use in soft self-healing devices, with the main focus on wearable devices. Following a brief introduction of conventional self-healing gels, this review summarizes the current strategies for synthesizing self-healing gels, comparing the properties of polymeric and small molecular self-healing gels. Some of the strengths and weaknesses of these two types of self-healing gels are clearly highlighted. Several typical instances to outline the emerging applications of self-healing gels with partially or fully self-healing devices/materials, including wearable sensors, supercapacitors, lithium batteries, and coatings, are provided. Finally, the current challenges and future perspectives regarding the further development of self-healing gels are also discussed.

Recent development and biomedical applications of self-healing hydrogels

Abstract: Introduction: Hydrogels are of special importance, owing to their high-water content and various applications in biomedical and bio-engineering research. Self-healing properties is a common phenomenon in living organisms. Their endowed property of being able to self-repair after physical/chemical/mechanical damage to fully or partially its original properties demonstrates their prospective therapeutic applications. Due to complicated preparation and selection of suitable materials, the application of many host–guest supramolecular polymeric hydrogels are so limited. Thus, the design and construction of self-repairing material are highly desirable for effectively increase in the lifetime of a functional material. However, recent advances in the field of materials science and bioengineering and nanotechnology have led to the design of biologically relevant self-healing hydrogels for therapeutic applications. This review focuses on the recent development of self-healing hydrogels for biomedical appli...