Stress Concentration Factor-Based Hot-Spot Stress Prediction Model for the Web-Gap Weld of Main Girder in Steel Truss Bridge

Chuanxi Li,Bohai Ji,Zhongqiu Fu,Yue Yao 대한토목학회 2024 KSCE Journal of Civil Engineering Vol.28 No.1

Fatigue cracking is one of the main diseases of steel bridges in operation stage. Scientific evaluation is of great significance to improve structural durability. However, obtaining the hot-spot stress (HSS) extrapolation point is challenging due to limited space around certain structural details in steel bridges. To overcome this limitation, a HSS prediction method incorporating the stress concentration factor (SCF) was proposed. Additionally, a structural mechanics model based on the mechanical characteristics of the web gap in the main girder of a steel truss bridge was established to calculate its nominal stress. Experimental and numerical simulations have been conducted to investigate the effects of various geometric parameters of the web gap on the SCFs. On this basis, a formula for predicting the SCF in web-gap weld was developed using multiple linear stepwise regression analysis. A fatigue evaluation framework considering the SCF for the web-gap weld were proposed. The result shows the web gap is affected by the joint actions of rotation and displacement, with the web gap of the end floor beam being more prone to fatigue damage. Moreover, the structural mechanics model considering the joint actions of rotation and displacement aligns better with the actual stress characteristics. The proposed SCF prediction formula for the web-gap weld demonstrates an error of less than 5% compared to the FE results. The fatigue damage obtained by the proposed HSS prediction method is consistent with the traditional extrapolation method, hence validating the feasibility and reliability of the proposed approach.

Water Dispersible Graphene Sheets Produced from Unassembled Graphene–Polyaniline Nanohybrids

Qi Li,Denian Li,Lijie Dong,Fan Sun,Jing Huang,Haian Xie,Chuanxi Xiong 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2015 NANO Vol.10 No.1

We present an effcient process for producing water dispersible graphene sheets from unassembled graphene–polyaniline nanohybrids. The result of atomic force microscopy reveals that over 80% of thus-prepared graphitic sheets are single layers with typical thickness of approximately 0.8 nm. The proportion of modifying molecules in the product is found to be as low as 3.0 wt.%, as determined by elemental analysis. Along with its fascinating water dispersibility and remarkably high electrical conductivity, such material is anticipated to be very promising for use in graphene-based nanoelectronics and high-performance composites.

Hepatotoxic mechanism of diclofenac sodium on broiler chicken revealed by iTRAQ-based proteomics analysis

Chuanxi Sun,Tianyi Zhu,Yuwei Zhu,Bing Li,Jiaming Zhang,Yixin Liu,Changning Juan,Shifa Yang,Zengcheng Zhao,Renzhong Wan,Shuqian Lin,Bin Yin 대한수의학회 2022 Journal of Veterinary Science Vol.23 No.4

Background: At the therapeutic doses, diclofenac sodium (DFS) has few toxic side effects on mammals. On the other hand, DFS exhibits potent toxicity against birds and the mechanisms remain ambiguous. Objectives: This paper was designed to probe the toxicity of DFS exposure on the hepatic proteome of broiler chickens. Methods: Twenty 30-day-old broiler chickens were randomized evenly into two groups (n = 10). DFS was administered orally at 10 mg/kg body weight in group A, while the chickens in group B were perfused with saline as a control. Histopathological observations, serum biochemical examinations, and quantitative real-time polymerase chain reaction were performed to assess the liver injury induced by DFS. Proteomics analysis of the liver samples was conducted using isobaric tags for relative and absolute quantification (iTRAQ) technology. Results: Ultimately, 201 differentially expressed proteins (DEPs) were obtained, of which 47 were up regulated, and 154 were down regulated. The Gene Ontology classification and Kyoto Encyclopedia of Genes and Genomes pathway analysis were conducted to screen target DEPs associated with DFS hepatotoxicity. The regulatory relationships between DEPs and signaling pathways were embodied via a protein-protein interaction network. The results showed that the DEPs enriched in multiple pathways, which might be related to the hepatotoxicity of DFS, were “protein processing in endoplasmic reticulum,” “retinol metabolism,” and “glycine, serine, and threonine metabolism.” Conclusions: The hepatotoxicity of DFS on broiler chickens might be achieved by inducing the apoptosis of hepatocytes and affecting the metabolism of retinol and purine. The present study could provide molecular insights into the hepatotoxicity of DFS on broiler chickens.

Computer Game System Modeling and Searching Algorithm for Occupancy of Niujiu Card

Chuanxi Zhang,Dongmei Li,Cong Dai 보안공학연구지원센터 2016 International Journal of Hybrid Information Techno Vol.9 No.3

As a carrier of artificial intelligence research, computer game can establish a sound theoretical foundation for the research of non-zero-sum card games with imperfect information. In this paper, we first propose a game model based on the finite Moore automaton, which illustrates the implementation of the model for Niujiu card. At the same time, a novel search strategy combining IMP-minimax and Monte Carlo algorithm is presented in this model. Through the given algorithm, this paper accomplishes the simulation, including not only the process of minimal and optimal occupancy for the first player, but the available frequency of special card type. Experiments show that our model and algorithm are feasible and effective.

Hepatotoxic mechanism of diclofenac sodium on broiler chicken revealed by iTRAQ-based proteomics analysis

Sun, Chuanxi,Zhu, Tianyi,Zhu, Yuwei,Li, Bing,Zhang, Jiaming,Liu, Yixin,Juan, Changning,Yang, Shifa,Zhao, Zengcheng,Wan, Renzhong,Lin, Shuqian,Yin, Bin 대한수의학회 2022 Journal of Veterinary Science Vol.23 No.3

Background: At the therapeutic doses, diclofenac sodium (DFS) has few toxic side effects on mammals. On the other hand, DFS exhibits potent toxicity against birds and the mechanisms remain ambiguous. Objectives: This paper was designed to probe the toxicity of DFS exposure on the hepatic proteome of broiler chickens. Methods: Twenty 30-day-old broiler chickens were randomized evenly into two groups (n = 10). DFS was administered orally at 10mg/kg body weight in group A, while the chickens in group B were perfused with saline as a control. Histopathological observations, serum biochemical examinations, and quantitative real-time polymerase chain reaction were performed to assess the liver injury induced by DFS. Proteomics analysis of the liver samples was conducted using isobaric tags for relative and absolute quantification (iTRAQ) technology. Results: Ultimately, 201 differentially expressed proteins (DEPs) were obtained, of which 47 were up regulated, and 154 were down regulated. The Gene Ontology classification and Kyoto Encyclopedia of Genes and Genomes pathway analysis were conducted to screen target DEPs associated with DFS hepatotoxicity. The regulatory relationships between DEPs and signaling pathways were embodied via a protein-protein interaction network. The results showed that the DEPs enriched in multiple pathways, which might be related to the hepatotoxicity of DFS, were "protein processing in endoplasmic reticulum," "retinol metabolism," and "glycine, serine, and threonine metabolism." Conclusions: The hepatotoxicity of DFS on broiler chickens might be achieved by inducing the apoptosis of hepatocytes and affecting the metabolism of retinol and purine. The present study could provide molecular insights into the hepatotoxicity of DFS on broiler chickens.

ONE-STEP SYNTHESIS OF BIOCOMPATIBLE CHITOSAN/NaGdF 4 :Eu 3 þ NANOCOMPOSITE WITH FLUORESCENT AND MAGNETIC PROPERTIES FOR BIOIMAGING

HUI LI,QUAN LIN,CHUANXI WANG,YINGNAN JIANG,ZHANCHEN CUI 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2014 NANO Vol.9 No.1

Lanthanide-doped luminescent nanoscale materials have great potential applications in biologicalresearches. Herein, we reported a novel and mild method for one-step synthesis of chitosan/NaGdF 4 :Eu 3 þnanocomposites. The luminescent Eu 3 þions and magnetic resonance imaging(MRI) contrast agent Gd 3 þions were incorporated to these biocompatible nanocomposites. Theresultant nanocomposites exhibited strong °uorescence and attractive magnetic features. Thenanocomposites also have pure hexagonal phase with uniform size of about 65 nm. FT-IR spectrarevealed that these nanocomposites were successfully coated by hydrophilic chitosan, whoseamine groups conferred the nanocomposites excellent dispensability in aqueous solution. Besides,the MTT assay and laser confocal microscopy images have con¯rmed the good biocompatibilityof the nanocomposites. These results indicated that the as-prepared nanocomposites could beused as an excellent targeted imaging agent in biological felds.

Fatigue evaluation and CFRP strengthening of diaphragm cutouts in orthotropic steel decks

Lu Ke,Chuanxi Li,Jun He,Yongjun Lu,Yang Jiao,Yongming Liu 국제구조공학회 2021 Steel and Composite Structures, An International J Vol.39 No.4

The cracking at the transverse diaphragm cutout is one of the most severe fatigue failures threatening orthotropic steel decks (OSDs), whose mechanisms and crack treatment techniques have not been fully studied. In this paper, full-scale experiments were first performed to investigate the fatigue performance of polished cutouts involving the effect of an artificial geometrical defect. Following this, comparative experimental testing for defective cutouts strengthened with carbon fiber-reinforced polymer (CFRP) was carried out. Numerical finite element analysis was also performed to verify and explain the experimental observations. Results show that the combinative effect of the wheel load and thermal residual stress constitutes the external driving force for the fatigue cracking of the cutout. Initial geometrical defects are confirmed as a critical factor affecting the fatigue cracking. The principal stress 6 mm away from the free edge of the cutout can be adopted as the nominal stress of the cutout during fatigue evaluation, and the fatigue resistance of polished cutouts is higher than Grade A in AASHTO specification. The bonded CFRP system is highly effective in extending the fatigue life of the defective cutouts. The present study provides some new insights into the fatigue evaluation and repair of OSDs.

CONTRACTION OF HOROSPHERE-CONVEX HYPERSURFACES BY POWERS OF THE MEAN CURVATURE IN THE HYPERBOLIC SPACE

Guo, Shunzi,Li, Guanghan,Wu, Chuanxi Korean Mathematical Society 2013 대한수학회지 Vol.50 No.6

This paper concerns the evolution of a closed hypersurface of the hyperbolic space, convex by horospheres, in direction of its inner unit normal vector, where the speed equals a positive power ${\beta}$ of the positive mean curvature. It is shown that the flow exists on a finite maximal interval, convexity by horospheres is preserved and the hypersurfaces shrink down to a single point as the final time is approached.

DEFORMING PINCHED HYPERSURFACES OF THE HYPERBOLIC SPACE BY POWERS OF THE MEAN CURVATURE INTO SPHERES

Guo, Shunzi,Li, Guanghan,Wu, Chuanxi Korean Mathematical Society 2016 대한수학회지 Vol.53 No.4

This paper concerns closed hypersurfaces of dimension $n{\geq}2$ in the hyperbolic space ${\mathbb{H}}_{\kappa}^{n+1}$ of constant sectional curvature evolving in direction of its normal vector, where the speed equals a power ${\beta}{\geq}1$ of the mean curvature. The main result is that if the initial closed, weakly h-convex hypersurface satisfies that the ratio of the biggest and smallest principal curvature at everywhere is close enough to 1, depending only on n and ${\beta}$, then under the flow this is maintained, there exists a unique, smooth solution of the flow which converges to a single point in ${\mathbb{H}}_{\kappa}^{n+1}$ in a maximal finite time, and when rescaling appropriately, the evolving hypersurfaces exponential convergence to a unit geodesic sphere of ${\mathbb{H}}_{\kappa}^{n+1}$.

Contraction of horosphere-convex hypersurfaces by powers of the mean curvature in the hyperbolic space

Shunzi Guo,Guanghan Li,Chuanxi Wu 대한수학회 2013 대한수학회지 Vol.50 No.6

This paper concerns the evolution of a closed hypersurface of the hyperbolic space, convex by horospheres, in direction of its inner unit normal vector, where the speed equals a positive power β of the positive mean curvature. It is shown that the flow exists on a finite maximal interval, convexity by horospheres is preserved and the hypersurfaces shrink down to a single point as the final time is approached.