Investigations on Influence of Erection Process on Buckling of Large Span Structures by a Novel Numerical Method

Zhongwei Zhao,Zhi-Hua Chen,Hongbo Liu,Bingzhen Zhao 한국강구조학회 2016 International Journal of Steel Structures Vol.16 No.3

The erection process of long-span spatial structures is significantly nonlinear which is often accompanied by variations in boundary condition and material property. Many researchers have conducted investigations on construction simulation of complex structures. But few investigate influence of erection process on buckling behavior of structures in service. A method for estimating the influence was proposed. The reliability and accuracy of this method was validated. Then three kinds of structures were analyzed to estimate influence of erection process. The results indicate that some kinds of structures are sensitive to erection process. Influence of erection process on buckling capacity should be considered appropriately.

A Novel Numerical Method for Considering Friction During Pre-stressing Construction of Cable-Supported Structures

Zhongwei Zhao,Bing Liang,Renzhang Yan 한국강구조학회 2018 International Journal of Steel Structures Vol.18 No.5

Suspen-dome structures are extensively used due to their superiority over traditional structures. The friction between cable and joints may severely infl uence the distribution of cable force, especially during the pre-stressing construction period. An accurate and effi cient numerical method has not yet been developed that can be used for estimating the infl uence of friction on cable force distribution. Thus, this study proposes an effi cient friction element to simulate friction between cable and joint. A fl owchart for estimating the value of friction force is introduced. These novel numerical methods were adopted to estimate the infl uence of friction on cable force distribution. The accuracy and effi ciency of these numerical methods were validated through numerical tests.

Optimizing the Construction Procedures of Large-span Structures Based on a Real-coded Genetic Algorithm

Zhongwei Zhao,Han Zhu,Zhi-Hua Chen,Yansheng Du 한국강구조학회 2015 International Journal of Steel Structures Vol.15 No.3

The erection phase is the most vulnerable period in the life of a structure. However, no mature and effective method for optimizing the construction procedures of large-span steel structures is yet available. Thus, proposing an optimization method for constructing such structures is critical. A real-coded genetic algorithm (GA) was proposed in the present work, and the selection, crossover, and mutation operators were programmed. The proposed algorithm is effective in optimizing integer combinations and sequences, such as an unloading sequence. A series of problems that occurred during the erection of conchshaped complex large steel structures was optimized using the proposed method. Optimum analysis was conducted using MATLAB and the general finite element software ANSYS. The optimal layouts of the lifting points, false work, and unloading sequence were derived. The influence of the GA parameters on its convergence efficiency was also studied. Therefore, the proposed GA method is reliable and effective for optimizing the construction procedures of large-span steel structures.

Low-temperature and solvent-free production of biomass-derived diesel-range C17 precursor via one-pot cascade acylation–alkylation over Sn4+-montmorillonite

Zhongwei Wang,Hu Li,Wenfeng Zhao,Song Yang 한국공업화학회 2018 Journal of Industrial and Engineering Chemistry Vol.66 No.-

A novel carbon-increasing catalytic route via one-pot cascade acylation–alkylation of biomass-derived 2-methylfuran and acetic anhydride over Sn4+-exchanged K-10 montmorillonite (Sn4+-K-10) was demonstrated to be highly efficient for the production of C17 oxygenate 1,1,1-tris(5-methyl-2-furyl)ethane with a high yield of 87% and 90% selectivity at 60 °C in 8 h under solvent-free conditions. Characterization techniques manifested Sn4+-K-10 to have layered and mesoporous (5.7 nm) texture structure, Lewis–Brønsted acid paired sites and uniformly dispersed Sn species, which greatly contributed to the predominant reactivity and recyclability of Sn4+-K-10. Systematic studies based on GC–MS and NMR were also conducted to elucidate the catalytic mechanism.

The Step-by-Step Model Technology Considering Nonlinear Effect Used for Construction Simulation Analysis

Zhihua Chen,Zhongwei Zhao,Han Zhu,Xiaodun Wang,Xiangyu Yan 한국강구조학회 2015 International Journal of Steel Structures Vol.15 No.2

Long-span spatial structures have advantages over other structural systems in terms of novelty and aesthetics in architectural form. However, the complexity of stress distribution causes these kinds of structures to change significantly between the construction and utilization stages. One-time loading method was used in the traditional design method to calculate and evaluate structural stress and structural deflection, either of which could cause problems in component size and residual stress during construction process. Therefore, construction simulation analysis of these structures must be performed. Element birth and death technology and step-by-step model technology (SSMT) are the main approaches in the finite element method used in construction analysis. This paper proposes a theory basis for the SSMT that was used in the constructional analysis of the Yujiapu Railway Station Building. Results obtained by the proposed method were compared with those by element birth and death technology. In addition, the preset construction deformation value was calculated to validate the correctness and efficiency of the proposed method.

Axial Compression Performance of Steel Box Columns with Different Strengthening Schemes

Yuan Yang,Zhi-Hua Chen,Zhongwei Zhao,Xiaoke Liu 한국강구조학회 2017 International Journal of Steel Structures Vol.17 No.2

Welding the reinforced component on the surface of a steel structure is a common method to reinforce steel structures in practical engineering. Work efficiency is low in actual construction because of continuous welding. Intermittent welding was adopted in this study to address this issue. The axial compression performance of reinforced steel columns in an actual project was studied through experiments and with the numerical method. The influence of different intermittent welding reinforcement schemes on the reinforcement of steel box columns was analyzed. Steel box columns with different weld intervals were placed relatively close because of their failure mechanism. The discontinuous welding reinforcement scheme reduced cost and improved efficiency. A simplified numerical model was established to conduct a parametrical analysis. An improved reinforcement scheme was proposed based on the analyzed results. The improved reinforcement scheme enhanced the load conditions and strength of steel angles.

A Simplified Numerical Model for Post-tensioned Steel Connections with Bolted Angles

Zhi-Hua Chen,Hongxing Li,Zhongwei Zhao,Haiqing Liu 한국강구조학회 2017 International Journal of Steel Structures Vol.17 No.4

Post-tensioned (PT) self-centering beam–column connections has been developed for its good seismic performance. Many researchers have investigated its mechanical behavior by numerical or experimental method. Prior researches have indicated that the analysis by elaborate FE models is very time consuming. To overcome this disadvantage, a simplified numerical model was established in this paper. The accuracy of results derived by this model was validated against prior investigations on interior PT connections with top-and-seat angles. Influence of initial PT force on mechanical behavior of PT connection was investigated. The Geometric and material nonlinearities, and strands can be considered in the modeling. A planar steel frame structure was established and hysteretic analysis was conducted. Results indicated that the computational cost can be greatly reduced by this model.

Application of Brodmann’s Area Maps for Cortical Localization of Tactile Perception Evoked by Fabric Touch

Qicai Wang,Yuan Tao,Jie Yuan,Zhaohui Jiang,Zuowei Ding,Zhongwei Zhang,Zhao Jia,Jing Wang 한국섬유공학회 2019 Fibers and polymers Vol.20 No.4

Different sensations are generated when we touch textiles with different performance. The mechanical propertiesrelated to fabric touch have been studied for a long time, the relationship between which and the subjective feelings is wellunderstood. However, the cognitive mechanism of our brain on the tactile perception evoked by fabric touch were rarelystudied. The relationship between mechanical properties of fabrics and the brain response in different areas is the vacancy ofthe study but urgent problem. In our previous study, the advanced technology of fMRI was proved to be an effective tool fordetecting brain response evoked by tactile stimulation of fabric touch with high spatial resolution. Now in this study, furtherfMRI experiments were conducted to observe brain response when participants touched different fabrics using their fingers ina specified way, and the most widely recognized functional atlas, Brodmann’s area maps, were applied to locate the corticalactivations in functional areas. Activations in the participants’s brain in different Brodmann areas was compared with themechanical preperties of the fabric samples tested by the instruments of KES-FB. The results showed that activationinformation in the participants’ brain can distinguish the fabric samples very well. Activations in several Brodmann areas areclosely connected with different tactile preperties of the fabrics. Therefore, Brodmann’s area maps were proved to be a usefulfunctional atlas for cortical localization of tactile perception evoked by fabric touch.

MLL4 Regulates the Progression of Non-Small-Cell Lung Cancer by Regulating the PI3K/AKT/SOX2 Axis

Yang Yang,Rongfang Qiu,Qiaoyou Weng,Ziwei Xu,Jingjing Song,Siyu Zhao,Miaomiao Meng,Dengke Zhang,Chunli Kong,Hailin Wang,Min Xu,Zhongwei Zhao,Jiansong Ji 대한암학회 2023 Cancer Research and Treatment Vol.55 No.3

Purpose Mixed-lineage leukemia protein 4 (MLL4/KMT2D) is a histone methyltransferase, and its mutation has been reported to be associated with a poor prognosis in many cancers, including lung cancer. We investigated the function of MLL4 in lung carcinogenesis. Materials and Methods RNA sequencing (RNA-seq) in A549 cells transfected with control siRNA or MLL4 siRNA was performed. Also, we used EdU incorporation assay, colony formation assays, growth curve analysis, transwell invasion assays, immunohistochemical staining, and in vivo bioluminescence assay to investigate the function of MLL4 in lung carcinogenesis. Results We found that MLL4 expression was downregulated in non–small cell lung cancer (NSCLC) tissues compared to adjacent normal tissues and tended to decrease with disease stage progression. We analyzed the transcriptomes in control and MLL4- deficient cells using high-throughput RNA deep sequencing (RNA-seq) and identified a cohort of target genes, such as SOX2, ATF1, FOXP4, PIK3IP1, SIRT4, TENT5B, and LFNG, some of which are related to proliferation and metastasis. Our results showed that low expression of MLL4 promotes NSCLC cell proliferation and metastasis and is required for the maintenance of NSCLC stem cell properties. Conclusion Our findings identify an important role of MLL4 in lung carcinogenesis through transcriptional regulation of PIK3IP1, affecting the PI3K/AKT/SOX2 axis, and suggest that MLL4 could be a potential prognostic indicator and target for NSCLC therapy.