http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Push-out tests on stud shear connectors with constrained structure of steel-concrete composite beams
Jingjing Qi,Zuwei Xie,Hua Cao,Zhi Huang,Weirong Lv,Weihua Shi 국제구조공학회 2022 Structural Engineering and Mechanics, An Int'l Jou Vol.83 No.6
The stud shear connector is the main force transfer member in the steel-concrete composite member, and the mechanical behavior is very complicated in the concrete. The concrete around the stud is subjected to the pry-out local pressure concentration of the stud, which can easily produce splitting mirco-cracks. In order to solve the problem of pry-out local splitting of stud shear connector, a kind of stud shear connector with constraint measure is proposed in this paper. Through the push-out test, the interface shear behavior of the new stud shear connector between steel and concrete flange plate was studied, and the difference between the new stud shear connector and the traditional stud connector was compared. The results show that the stud shear connector with constraint measure can effectively avoid the adverse effect of local pressure splitting by relying on its own constraint measure. The shear stiffness of the interface between steel and concrete flange plates is greatly improved, which provides a theoretical basis for the design of strong connection coefficient of steel-concrete composite structures.
Effect of Degumming Methods on the Degradation Behavior of Silk Fibroin Biomaterials
Luping Wang,Zuwei Luo,Qiang Zhang,Yupin Guan,Junyi Cai,Renchuan You,Xiufang Li 한국섬유공학회 2019 Fibers and polymers Vol.20 No.1
Degradation behavior is a key consideration in the field of silk fibroin (SF) biomaterials. Degumming to remove sericin is a prerequisite for SF purification; however, the impact of degumming on the degradation behavior of SF biomaterials has not been established. In this study, two different degumming systems, Na2CO3 and NaHCO3, were used. Na2CO3 exhibited higher degumming efficiency but caused greater degradation of the fibroin. The results demonstrated that NaHCO3 degumming could afford regenerated SF with higher molecular weight, resulting in SF films with higher mechanical strengths. The enzymatic degradation behaviors indicated that the SF films prepared by the Na2CO3 degumming process showed faster degradation, revealing that the choice of degumming method has a substantial impact on the biodegradation of SF-based materials. The results showed that manipulating the degumming conditions can be used to tune the molecular weight of the SF, in turn providing control over the degradation rate of SF biomaterials.
Facile Preparation of Mechanical Reinforced and Biocompatible Silk Gels
Qiang Zhang,Guocong Han,Chen Lu,Qiusheng Wang,Xiufang Li,Zuwei Luo,Renchuan You,Shuqin Yan 한국섬유공학회 2019 Fibers and polymers Vol.20 No.4
Nontoxic and controllable way to fabricate silk fibroin (SF) gel with high mechanical properties is of critical important to biomaterial in tissue engineering. Electrochemically triggered electrophoretic migration and electric charge of the silk molecules both contributed to SF microspheres and electronic gel (e-gel) formation by sol-gel transition. In this study, a novel silk pH e-gel with higher mechanical property was prepared by combining low-voltage electric fields with isoelectric point (pI) adjustment. This green process was mild and friendly without chemical crosslinker. Compressive modulus of the silk pH e-gel was up to 70 MPa that was significantly higher than that of SF gelation spontaneously. Furthermore, analysis of molecule conformation of the silk pH-e-gel demonstrated that most of random coil structures transformed into α-helix and a little β-sheet structures during this process. The silk pH e-gel was loaded with rhodamine B and showed an obvious sustainable release profile. Accumulation releasing amounts was approximately 60 % at day 9. Cytocompatibility of the silk pH-e-gel was evaluated by epithelial cell. The results showed that the gels could support the cell growth and proliferation in vitro. Finally, gel biodegradation was assessed by protease XIV. After biodegradation for 28 days, remaining weight of the gel was about 20.23±2.59 wt%, indicating its good biodegradability. This novel process was established successfully by combining low voltage field with pH-control, which provided an alternative material for regenerative medicine.