In this study, biomimetic sodium alginate (SA)/silk fibroin (SF) scaffolds were successfully fabricated by supercritical CO2 technology. The SA/SF scaffolds exhibited an interconnected porous and extracellular matrix (ECM)-like nanofibrous structures. Moreover, the SA microparticles were embedded in the SF scaffolds. Increasing the content of SA microparticles could improve tensile strength and compressive strength of the SF scaffolds and reduce the porosity of the SF scaffolds. The addition of the SA microparticles could also regulate the degradation rate of the SA/SF scaffolds. Furthermore, the results of in vitro biocompatibility evaluation, indicated that the SA/SF scaffolds exhibited no obvious cytotoxicity and higher cell adhesion ability and were more favorable for L929 fibroblasts proliferation than pure SF scaffolds. Therefore, the SA/SF scaffolds with ECM-like nanofibrous and interconnected porous structure have potential application in skin tissue engineering. 相似文献
More and more complicated conceptual design of ship’s engine room (CDSER) heavily depends on designers’ engineering knowledge and existing ship data. To achieve intelligent design at the initial ship design stage, many researchers have made much significant progress in this field, however, most of them only focused on how to find the similar constructed ships. At present, how to utilize these existing data remains an untouched topic. In order to make good use of the existing data and reduce the dependence on designers’ experience, a novel system named Expert System for Aided Conceptual Design of Ship’s Engine Room Automation (ESACD), is elaborated in this study. With the support of the constructed Ship Data Warehouse System, two core subsystems Configuration Selection Assistant (CSA) and Design Scheme Decision Assistant (DSDA) are included in ESACD. A promising approach integrating Fuzzy c-means algorithm (FCM) and Rough Sets Theory (RST) to extract configuration rules from the stored data is adopted in CSA. According to engineers’ proposals, RST is utilized to reason knowledge in incomplete scheme information systems for getting design scheme rules in DSDA, which are useful suggestions for engineers to get better schemes at this stage. Finally, the validity and necessity of this interactive expert system are demonstrated through the CDSER of a new 50,000 DWT Handymax bulk carrier. It is proved that ESACD can efficiently facilitate rapid and intelligent design in CDSER, and reduce the cost of a new ship design. 相似文献
In this article, based on partial differential equations (PDEs), the flexible manipulator system with both dead-zone input and state constraints is studied. The dynamic model of the flexible manipulator system is described by PDEs. The parameters of the dead-zone input are unknown, and the state constraint problem is also considered. An adaptive approach is proposed to offset the effects caused by dead-zone input. Thus, to guarantee that all states remain within their respective constraint regions, the boundary control law based on the barrier Lyapunov function is given, and an adaptive controller is designed. According to the Lyapunov analysis method, the control method is given to ensure that all signals of the closed-loop system are bounded and all states satisfy the constraint conditions. Finally, simulation results show the effectiveness of the proposed control method in this article. 相似文献
Morphology transformation and crystal growth strategies of metal oxide semiconductors are still extensively studied in material science recently, because the morphology and crystallinity significantly affect the physicochemical characteristics of metal oxide nanomaterials. However, understanding the morphology changes of α-MoO3 induced by annealing is still a challenge. Herein, the nanostructure transition of α-MoO3 induced by the annealing temperature is carefully investigated via the XRD and SEM methods. It can be found that crystallization is highly dependent on the annealing temperature. Interestingly, the MoO3 nanoflowers can change into nanosheets at 500 °C. Afterward, the nanosheets turned into microrods with the increase in annealing temperature due to the continuous growth of MoO3 crystal. On the other hand, the sensing performances of various MoO3 nanostructures are studied toward ethanol gas. Compared to the MoO3 nanoflowers and microrods, the MoO3 nanosheets-based sensor exhibits superior sensing performance to ethanol, and the maximum response value is 8.06.