Nonlinear finite element analysis of circular concrete-filled steel tube structures

Tengfei Xu,Tianyu Xiang,Renda Zhao,Yulin Zhan 국제구조공학회 2010 Structural Engineering and Mechanics, An Int'l Jou Vol.35 No.3

The structural behaviors of circular concrete filled steel tube (CFT) structures are investigated by nonlinear finite element method. An efficient three-dimensional (3D) degenerated beam element is adopted. Based on those previous studies, a modified stress-strain relationship for confined concrete which introduces the influence of eccentricity on confining stress is presented. Updated Lagrange formulation is used to consider the geometrical nonlinearity induced by large deformation effect. The nonlinear behaviors of CFT structures are investigated, and the accuracy of the proposed constitutive model for confined concrete is mainly concerned. The results demonstrate that the confining effect in CFT elements subjected to combining action of axial force and bending moment is far sophisticated than that in axial loaded columns, and an appropriate evaluation about this effect may be important for nonlinear numerical simulation of CFT structures.

Nonlinear finite element analysis of circular concrete-filled steel tube structures

Xu, Tengfei,Xiang, Tianyu,Zhao, Renda,Zhan, Yulin Techno-Press 2010 Structural Engineering and Mechanics, An Int'l Jou Vol.35 No.3

The structural behaviors of circular concrete filled steel tube (CFT) structures are investigated by nonlinear finite element method. An efficient three-dimensional (3D) degenerated beam element is adopted. Based on those previous studies, a modified stress-strain relationship for confined concrete which introduces the influence of eccentricity on confining stress is presented. Updated Lagrange formulation is used to consider the geometrical nonlinearity induced by large deformation effect. The nonlinear behaviors of CFT structures are investigated, and the accuracy of the proposed constitutive model for confined concrete is mainly concerned. The results demonstrate that the confining effect in CFT elements subjected to combining action of axial force and bending moment is far sophisticated than that in axial loaded columns, and an appropriate evaluation about this effect may be important for nonlinear numerical simulation of CFT structures.

Reversible MoS₂ Origami with Spatially Resolved and Reconfigurable Photosensitivity

Xu, Weinan,Li, Tengfei,Qin, Zhao,Huang, Qi,Gao, Hui,Kang, Kibum,Park, Jiwoong,Buehler, Markus J.,Khurgin, Jacob B.,Gracias, David H. American Chemical Society 2019 Nano letters Vol.19 No.11

<P>Two-dimensional layered materials (2DLMs) have been extensively studied in a variety of planar optoelectronic devices. Three-dimensional (3D) optoelectronic structures offer unique advantages including omnidirectional responses, multipolar detection, and enhanced light-matter interactions. However, there has been limited success in transforming monolayer 2DLMs into reconfigurable 3D optoelectronic devices due to challenges in microfabrication and integration of these materials in truly 3D geometries. Here, we report an origami-inspired self-folding approach to reversibly transform monolayer molybdenum disulfide (MoS<SUB>2</SUB>) into functional 3D optoelectronic devices. We pattern and integrate monolayer MoS<SUB>2</SUB> and gold (Au) onto differentially photo-cross-linked thin polymer (SU8) films. The devices reversibly self-fold due to swelling gradients in the SU8 films upon solvent exchange. We fabricate a wide variety of optically active 3D MoS<SUB>2</SUB> microstructures including pyramids, cubes, flowers, dodecahedra, and Miura-oris, and we simulate the self-folding mechanism using a coarse-grained mechanics model. Using finite-difference time-domain (FDTD) simulation and optoelectronic characterization, we demonstrate that the 3D self-folded MoS<SUB>2</SUB> structures show enhanced light interaction and are capable of angle-resolved photodetection. Importantly, the structures are also reversibly reconfigurable upon solvent exchange with high tunability in the optical detection area. Our approach provides a versatile strategy to reversibly configure 2D materials in 3D optoelectronic devices of broad relevance to flexible and wearable electronics, biosensing, and robotics.</P> [FIG OMISSION]</BR>

The chromosome-level reference genome of Cinnamomum camphora provides new insights into the angiosperm phylogeny and terpene biosynthesis

Tengfei Shen,Faxin Yu,Meng Xu,Yongda Zhong 강원대학교 산림과학연구소 2022 강원대학교 산림과학연구소 학술대회 Vol.2022 No.10

Cinnamomum camphora is widely distributed in southeastern of China and is a representative species of Laurales, which has important ecological and economic values due to its richness in plant secondary metabolites. In this study, the chromosome-level reference genome of C. camphora was published with a genome size of 670.29 Mb, of which contig N50 was 2.41 Mb and scaffold N50 was 60.19 Mb, and the duplicated sequences accounted for about half of the genome. Comparative genomic analysis showed that C. camphora underwent three whole-genome duplication (WGD) events, with the distant WGD event being an ε-replication event shared by angiosperm ancestors; the intermediate WGD event occurring before the divergence of Laurales and Magnoliales (Liriodendron chinense); and the recent event occurring approximately before the divergence within Laurales. In addition, we examined the expression of terpene synthesis-related genes in seven different tissues and found that DXS, DXR and HDR, the key limiting enzymes of the MEP pathway associated with monoterpene synthesis, were highly expressed in flowers. In addition, a total of 83 CcamTPS genes were predicted and annotated in the camphor tree genome, and most of them were highly expressed in leaves, stem tips and bark. The chromosomal-level reference genome of the C. camphora provides new insights into the special evolutionary status of magnoliids and terpene biosynthesis.

Dynamic analysis of thin-walled open section beam under moving vehicle by transfer matrix method

Xiang, Tianyu,Xu, Tengfei,Yuan, Xinpeng,Zhao, Renda,Tong, Yuqiang Techno-Press 2008 Structural Engineering and Mechanics, An Int'l Jou Vol.30 No.5

Three dimensional coupled bending-torsion dynamic vibrations of thin-walled open section beam subjected to moving vehicle are investigated by transfer matrix method. Through adopting the idea of Newmark-${\beta}$ method, the partial differential equations of structural vibration can be transformed to the differential equations. Then, those differential equations are solved by transfer matrix method. An iterative scheme is proposed to deal with the coupled bending-torsion terms in the governing vibration equations. The accuracy of the presented method is verified through two numerical examples. Finally, with different eccentricities of vehicle, the torsional vibration of thin-walled open section beam and vertical and rolling vibration of truck body are investigated. It can be concluded from the numerical results that the torsional vibration of beam and rolling vibration of vehicle increase with the eccentricity of vehicle. Moreover, it can be observed that the torsional vibration of thin-walled open section beam may have a significant nonlinear influence on vertical vibration of truck body.

Multifunctional nanozyme‑reinforced copper‑coordination polymer nanoparticles for drug‑resistance bacteria extinction and diabetic wound healing

Jiahui Zhao,Tengfei Xu,Jichao Sun,Haitao Yuan,Mengyun Hou,Zhijie Li,Jigang Wang,Zhen Liang 한국생체재료학회 2023 생체재료학회지 Vol.27 No.00

Background Drug-resistant bacterial infections in chronic wounds are a persistent issue, as they are resistant to antibiotics and can cause excessive inflammation due to generation of reactive oxygen species (ROS). An effective solution would be to not only combat bacterial infections but also scavenge ROS to relieve inflammation at the wound site. Scaffolds with antioxidant properties are attractive for their ability to scavenge ROS, and there is medical demand in developing antioxidant enzyme-mimicking nanomaterials for wound healing. Methods In this study, we fabricated copper-coordination polymer nanoparticles (Cu-CPNs) through a self-assembly process. Furthermore, ε-polylysine (EPL), an antibacterial and cationic polymer, was integrated into the Cu-CPNs structure through a simple one-pot self-assembly process without sacrificing the glutathione peroxidase (GPx) and superoxide dismutase (SOD)-mimicking activity of Cu-CPNs. Results The resulting Cu-CPNs exhibit excellent antioxidant propertiesin mimicking the activity of glutathione peroxidase and superoxide dismutase and allowing them to effectively scavenge harmful ROS produced in wound sites. The in vitro experiments showed that the resulting Cu-CPNs@EPL complex have superior antioxidant properties and antibacterial effects. Bacterial metabolic analysis revealed that the complex mainly affects the cell membrane integrity and nucleic acid synthesis that leads to bacterial death. Conclusions The Cu-CPNs@EPL complex has impressive antioxidant properties and antibacterial effects, making it a promising solution for treating drug-resistant bacterial infections in chronic wounds. The complex’s ability to neutralize multiple ROS and reduce ROS-induced inflammation can help relieve inflammation at the wound site.

Dynamic analysis of thin-walled open section beam under moving vehicle by transfer matrix method

Tianyu Xiang,Tengfei Xu,Xinpeng Yuan,Renda Zhao,Yuqiang Tong 국제구조공학회 2008 Structural Engineering and Mechanics, An Int'l Jou Vol.30 No.5

Three dimensional coupled bending-torsion dynamic vibrations of thin-walled open section beam subjected to moving vehicle are investigated by transfer matrix method. Through adopting the idea of Newmark-β method, the partial differential equations of structural vibration can be transformed to the differential equations. Then, those differential equations are solved by transfer matrix method. An iterative scheme is proposed to deal with the coupled bending-torsion terms in the governing vibration equations. The accuracy of the presented method is verified through two numerical examples. Finally, with different eccentricities of vehicle, the torsional vibration of thin-walled open section beam and vertical and rolling vibration of truck body are investigated. It can be concluded from the numerical results that the torsional vibration of beam and rolling vibration of vehicle increase with the eccentricity of vehicle. Moreover, it can be observed that the torsional vibration of thin-walled open section beam may have a significant nonlinear influence on vertical vibration of truck body.

Enrichment of C17:0-rich saturated fatty acids from sheep tail fat for adjuvant therapy of non-small-cell lung cancer

Xiaoqi Yu,Xiaoyi Liu,Yuanli Li,Huimin He,Xinxin Pei,Tengfei Ma,Yuanyuan Chen,Yi Wang,Hongxia Li,Wenchu Lin,Changzhi Xu,Buchang Zhang 한국식품과학회 2024 Food Science and Biotechnology Vol.33 No.8

Heptadecanoic acid (C17:0), an odd-chain saturated fatty acid (OCSFA) in ruminant lipid, has been demonstrated to be potential for treating cancers. Our results also showed that sheep tail fat (STF) with higher level of C17:0-containing saturated fatty acids (SFAs) whereas lower level of oleic acid (C18:1), performed remarkable inhibition against non-small-cell lung cancer (NSCLC) cells. To enrich the content of C17:0, a C17:0-rich SFA concentrate (HRSC) was prepared from STF by solvent crystallization and urea complexation methods (hexane/STF = 3.5/1, 4 °C for 8 h, and 80% ethanol/urea/free fatty acids = 8/1/1, 4 °C for 6 h). The content of C17:0 was up from 3.02 to 6.34% and the recovery was 4.17%. Biological experiments showed that HRSC exerted better antiproliferative effect against NSCLC cells. Moreover, HRSC performed enhanced inhibitory effect in A549 cell xenograft mouse model. Therefore, HRSC has the potential to be applied in adjuvant therapy for NSCLC.