Parametric study on bearing capacity of CFST members considering the concrete horizontal casting effect

Wenbo Sun,Yiqun Luo,Weijian Zhou,Wei Huang 국제구조공학회 2012 Steel and Composite Structures, An International J Vol.13 No.3

Concrete filled steel tubular (CFST) member has been widely used in the construction of highrise buildings for its high axial bearing capacity. It can also be applied on long-span structures such as spatial structures or bridges not only for its high bearing capacity but also for its construction convenience. Concrete casting effect of CFST member is considered in the study of its bearing capacity in this paper. Firstly, in order to authenticate the applicability of constitutive relationship and yield criterion of steel and concrete based on FEM, two ANSYS models are built to simulate and compared with other’s test. Secondly, in order to find the huge difference in bearing capacity due to different construction processes, two full-size CFST models are studied when they are horizontally cast and axially compressed. Finally, the effects of slenderness ratio (L/D) and confining parameter (D/t) of CFST members are studied to reveal the intrinsic links between bearing capacity and slenderness ratio or confining parameter.

Energy Evolution of Rock under Different Stress Paths and Establishment of a Statistical Damage Model

Wenbo Liu,Shuguang Zhang,Boyi Sun 대한토목학회 2019 KSCE Journal of Civil Engineering Vol.23 No.10

In consideration of the influence of energy dissipation on the rock compression process, the traditional elastic stress-strain relationship was improved by adding the energy release rate. The microintensity of the rock was assumed to satisfy the Weibull distribution. The improved stress-strain relationship was transformed into a triaxial stress-strain model in consideration of the loading damage combined with mesodamage mechanics. The characteristic points of the stress-strain curve and the experimental data were utilized to calculate the distribution parameters of the rock under different conditions. The model curve was compared with the experimental data. Results showed that the stress-strain curve of the rock has peak points in the conventional triaxial compression test, but the radial peak of the rock was not evident in the unloading test. The energy of the rock under the loading path was smaller than that under the unloading path. The model curve exhibited a high degree of fitting with the experimental data, and its correlation coefficient was relatively large (> 0.90), which indicated that the model can clearly represent the actual damage and evolution law of the surrounding rock. Furthermore, the established model can also reflect the rock’s stress-strain relationship, which can serve as a practical guide for relevant applications. Finally, the distribution parameters also reflected the evolution law of rock energy and provided a method for the assessment of rock energy and damage trend.

Simulation and Research of Boiler Combustion Process Based On the Improved RBF Neural Network

Rong Panxiang,Sun Jianpeng,Liu Zhaoyu,Yu Lin,Dong Wenbo 보안공학연구지원센터(IJUNESST) 2013 International Journal of u- and e- Service, Scienc Vol.6 No.5

Robust Image Watermarking via Perceptual Structural Regularity-based JND Model

( Chunxing Wang ),( Meiling Xu ),( Wenbo Wan ),( Jian Wang ),( Lili Meng ),( Jing Li ),( Jiande Sun ) 한국인터넷정보학회 2019 KSII Transactions on Internet and Information Syst Vol.13 No.2

A better tradeoff between robustness and invisibility will be realized by using the just noticeable (JND) model into the quantization-based watermarking scheme. The JND model is usually used to describe the perception characteristics of human visual systems (HVS). According to the research of cognitive science, HVS can adaptively extract the structure features of an image. However, the existing JND models in the watermarking scheme do not consider the structure features. Therefore, a novel JND model is proposed , which includes three aspects: contrast sensitivity function, luminance adaptation, and contrast masking (CM). In this model, the CM effect is modeled by analyzing the direction features and texture complexity, which meets the human visual perception characteristics and matches well with the spread transform dither modulation (STDM) watermarking framework by employing a new method to measure edge intensity. Compared with the other existing JND models, the proposed JND model based on structural regularity is more efficient and applicable in the STDM watermarking scheme. In terms of the experimental results, the proposed scheme performs better than the other watermarking scheme based on the existing JND models.

Pyrolysis mechanism of bastnaesite during roasting in N2 atmosphere: An in-situ study of gas products, phase transition, and kinetics

Qiang Zhang,Yongsheng Sun,Yuexin Han,Peng Gao,Wenbo Li 한국공업화학회 2023 Journal of Industrial and Engineering Chemistry Vol.124 No.-

The application of suspension magnetization roasting technology in ferruginous rare earth bearing orehas gained significant attention. Bastnaesite, due to its pyrolysis characteristics, has been proposed asa reductant for iron minerals. In this study, the pyrolysis of bastnaesite was investigated through variousin-situ methods. The results showed that during pyrolysis, CeOF and CO2 were first generated, followedby the reaction of CO2 with Ce2O3 and Ce7O12 to produce CO. Pyrolysis occurred initially on the particlesurface and then progressed inward. Increasing the roasting temperature promoted the pyrolysis of bastnaesiteand CO generation. The addition of CO2 during the roasting process enhanced the formation of CO. The pyrolysis kinetic mechanisms under isothermal and non-isothermal conditions were phaseboundarycontrolled reaction mechanism (n = 4) and phase-boundary controlled reaction mechanism(n = 2–4), respectively. This detailed analysis of the pyrolysis behavior of bastnaesite facilitates the efficientand low-carbon development of ferruginous rare earth ores through suspension magnetizationroasting.

Phase-field simulation of radiation-induced bubble evolution in recrystallized U-Mo alloy

Yanbo Jiang,Yong Xin,Wenbo Liu,Zhipeng Sun,Ping Chen,Dan Sun,Mingyang Zhou,Xiao Liu,Di Yun 한국원자력학회 2022 Nuclear Engineering and Technology Vol.54 No.1

In the present work, a phase-field model was developed to investigate the influence of recrystallizationon bubble evolution during irradiation. Considering the interaction between bubbles and grain boundary(GB), a set of modified Cahn-Hilliard and Allen-Cahn equations, with field variables and order parametersevolving in space and time, was used in this model. Both the kinetics of recrystallization characterized inexperiments and point defects generated during cascade were incorporated in the model. The bubbleevolution in recrystallized polycrystalline of UeMo alloy was also investigated. The simulation resultsshowed that GB with a large area fraction generated by recrystallization accelerates the formation andgrowth of bubbles. With the formation of new grains, gas atoms are swept and collected by GBs. Thesimulation results of bubble size and distribution are consistent with the experimental results.

Performance investigation of nanoscale thermal cloak by the perforated silicon film

Zhang Jian,Zhang Haochun,Zhang Dong,Sun Wenbo,Li Yiyi 한국물리학회 2022 Current Applied Physics Vol.35 No.-

In recent years, nanoscale thermal cloak, as a representative of nanoscale heat flux regulation devices, has attracted a lot of attention from researchers. However, the existing design methods are relatively complicated and all adopt constant temperature boundaries, the temperature changes constantly in the real environment, which greatly hinders its engineering applications. In this paper, inspired by phonon localization theory, we construct a nanoscale thermal cloak by a perforated silicon membrane and evaluate its cloaking performance and dynamic response. Results show that when the perforated area is fixed, the more the number of holes, the better the cloaking performance. In addition, the nanoscale thermal cloak still exhibits good cloaking performance in the dynamic environment. Finally, the cloaking mechanism is analyzed by calculating the phonon density of states (PDOS) and mode participation rate (MPR), and the reduction of thermal conductivity in the functional region is attributed to phonon localization.

Preparation method and device for functionally gradient materials based on PDMS

Guangyao Zhang,Fan Gao,Jinmei Sun,Wenbo Yu 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.6

Given the shortcomings of existing methods of preparing functionally gradient materials based on PDMS, such as insufficient raw material mixing, a single preparation method, and high preparation cost, a device that incorporates the production and preparation of functionally gradient products is proposed. Simulations using the COMSOL software were employed to determine an optimization model for the mixing conditions during the preparation of functionally gradient material mixtures. Furthermore, the mixing capabilities of the device were compared when using constant-size and variable-size stirrers. The simulation research results indicate that the preparation device, in combination with the variable-size stirrer, can effectively stir the mixing. The mixing efficiency of the device when using the variable-size stirrer increased by approximately 36 % from that when using the constant-size stirrer. Actual samples were prepared and observed using a Hitachi electron microscope at a 200x magnification. The observation results show that the SiC particles in the sample prepared with a variable-size stirrer were distributed more uniformly than those in the sample prepared with a constant-size stirrer. The product prepared using the proposed device met the conditions for manufacturing functionally gradient products.

Influence of the evolution of heat-resistant phases on elevated-temperature strengthening mechanism and deformation behavior in Al–Si multicomponent alloys

Meng Fanchao,Wu Yuying,Li Wenbo,Hu Kaiqi,Zhao Kai,Yang Huabing,Gao Tong,Sun Yue,Liu Xiangfa 한국물리학회 2022 Current Applied Physics Vol.39 No.-

Evolution of the heat-resistant phases and deformation behavior of α-Al matrix of four alloys have been characterized by SEM and EBSD. The strengthening mechanisms influenced by morphology and distribution of the heat-resistant phases were described. And the strain contouring of the α-Al matrix after deformation was rendered. The heat-resistant phases with block-like as reticular or semi-reticular network distribution exist in grain boundary can effectively provide elevated-temperature strength for alloys, while the strain contouring of α-Al matrix is mainly concentrated in the area with fewer intermetallic phases. It is shown that intermetallic phase evolution corresponds to extrusion treatment and the formation of eutectic Si and primary Si, highly interconnected networks of intermetallic phases exist in the alloy in which the primary Si and the eutectic Si are simultaneously present or disappeared. And only the disappearance of the primary Si and the extrusion treatment will destroy the network structure of the intermetallic phases. A reticular or semi-reticular microstructure is more capable of matching strength and plasticity and facilitating uniform deformation of the α-Al matrix. And the destruction of this microstructure is allowed to accommodate more plastic strain before failure.

Study on pharmacokinetics and tissue distribution of single dose oral tryptanthrin in Kunming mice by validated reversed-phase high-performance liquid chromatography with ultraviolet detection

Xiaoyan Zhang,Jie Xia,Wenjing Zhang,Yao Luo,Wenbo Sun,Wei Zhou 한국한의학연구원 2017 Integrative Medicine Research Vol.6 No.3

Background: Tryptanthrin is a major active constituent of several Chinese herbal plants, such as Isatidis radix. Tryptanthrin had been demonstrated to have several beneficial pharmacological effects in vitro for human diseases, including antitumor, anti-inflammatory and antibacteria activities. In contrast to the extensive in vitro investigations, the in vivo disposition process of tryptanthrin was explored limitedly. Methods: In this study, the pharmacokinetics (PK) and tissue distribution of tryptanthrin in Kunming mice following a single oral dose of 80 mg/kg tryptanthrin were investigated for the first time. Mouse plasma, liver, heart, spleen, lung, kidney and brain were collected and analyzed using a validated reversed-phase high-performance liquid chromatography with ultraviolet detection (RP-HPLC–UV) method after biological sample preparation by a simple liquid–liquid extraction. Results: The chromatographic analysis was performed on a Diamonsil C18 column (5 μm, 250 mm × 4.6 mm) and ultraviolet detection was set at a wavelength of 251 nm. The analysis was achieved with a mobile phase of methanol (A) and water (B) (60:40, v/v) at a flow rate of 1.0 mL/min. The method was linear over the concentration range of 4.0–400.0 μg/mL with a lower limit of quantification of 0.10–0.30 μg/mL. Inter- and intraday precisions (relative standard deviations %) were all within 2.93%. Recoveries of tryptanthrin were more than 86.44%. Maximal tryptanthrin concentrations in plasma and tissues of mice were reached within 2.5 hours. The actual highest concentration (Cmax) in mouse plasma was 3.13 μg/mL, the area under the curve (AUC0–t) was 9.38 h μg/mL, and the terminal half-life was 2.27 hours. The volume of distribution was 343.89 mL, the clearance rate was 204.58 mL/h, and the PK of tryptanthrin in mice after oral administration was fit to 2 compartment 1 st Order. After oral dosing of tryptanthrin to Kunming mice, the analyte was well distributed to the plasma and main tissues. Cmax was found in the liver with a mean value of 3.54 μg/g, followed by that in the kidney, lung, spleen, heart, and brain. Conclusion: In this study, a validated RP-HPLC–UV method was developed and successfully applied to PK and tissue distribution of oral tryptanthrin in mice. We confirmed that tryptanthrin was closely related and targeted to plasma, liver, kidney, and lung. These results indicate that tryptanthrin will have a good clinical application in the liver, kidney, or lung. The clinical use of tryptanthrin should focus on its pharmacodynamics and safety study in these tissues.