Shear resistance of steel–concrete–steel deep beams with bidirectional webs

Yu-Tao Guo,Xin Nie,Jiansheng Fan,Mu-Xuan Tao 국제구조공학회 2022 Steel and Composite Structures, An International J Vol.42 No.3

Steel–concrete–steel composite structures with bidirectional webs (SCSBWs) are used in large-scale projects and exhibit good mechanical performances and constructional efficiency. The shear behaviors of SCSBW deep beam members in key joints or in locations subjected to concentrated forces are of concern in design. To address this issue, experimental program is investigated to examine the deep-beam shear behaviors of SCSBWs, in which the cracking process and force transfer mechanism are revealed. Compared with the previously proposed truss model, it is found that a strut-and-tie model is more suitable for describing the shear mechanism of SCSBW deep beams with a short span and sparse transverse webs. According to the experimental analyses, a new model is proposed to predict the shear capacities of SCSBW deep beams. This model uses strut-and-tie concept and introduces web shear and dowel action to consider the coupled multi mechanisms. A stress decomposition method is used to distinguish the contributions of different shear-transferring paths. Based on case studies, a simplified model is further developed, and the explicit solution is derived for design efficiency. The proposed models are verified using experimental data, which are proven to have good accuracy and efficiency and to be suitable for practical application.

Hierarchical Porous BiOCl/LDHs Composites Templated from Cotton Fibers for Efficient Removal of Dyes from Aqueous Solution

Tao Zhang,Xinbin Nie,Xuejie Yue,Dongya Yang,Yuting Dai,Fengxian Qiu 한국섬유공학회 2018 Fibers and polymers Vol.19 No.3

Hierarchically structured BiOCl/LDHs composites with well-developed porosity and high surface area have been prepared by an in situ growth of BiOCl on the surfaces LDHs fibers, and their adsorption capacities and photocatalytic activities are investigated by using methylene blue (MB) as model pollutants. The results indicate that the BiOCl/LDHs composites possess high surface area up to 126.2 m2/g. The as-prepared BiOCl/LDHs composites exhibited higher adsorptive ability and improved photocatalytic activity compared to bare BiOCl particles and LDHs fibers based on the removal of MB in aqueous solution, showing that BiOCl/LDHs composites can be used as efficient environmentally friendly materials for dye wastewater treatment.

Kinetic and thermodynamic study of Eu(III) sorption on natural red earth in South China

Tao Yu,Wang-Suo Wu,Zhi-Rong Liu,Si-Wei Zhang,Zheng-Wei Nie 한국화학공학회 2013 Korean Journal of Chemical Engineering Vol.30 No.2

We did a kinetic and thermodynamic study of Eu(III) sorption on natural red earth (NRE) in South China as a function of contact time, pH values, ionic strength, humic acid (HA) and temperature under ambient conditions. Linear and nonlinear regression methods in selecting the optimum sorption isotherm were applied on the experimental data. The results suggest that sorption of Eu(III) on NRE can be described by a pseudo-second-order rate equation and strongly dependent on ionic strength at pH<7. Sorption of Eu(III) on NRE increased with increasing temperature,two-parameter and three-parameter isotherms were applied to analysis the equilibrium adsorption data, and a comparison of linear and nonlinear regression methods was done. The thermodynamic parameters (ΔH0, ΔS0 and ΔG0) of Eu(III)sorption on NRE at different temperatures were calculated from the temperature-dependent sorption isotherms, indicating that the sorption process of Eu(III) was spontaneous. The results showed that the nonlinear method is a better way to obtain the isotherm parameters and the data were in good agreement with the Freundlich isotherm model.

Fabrication and properties of reaction-bonded SiC prepared by gelcasting

Lifang Nie,Hongyu Gong,Tao Zhang,Yujun Zhang 한양대학교 세라믹연구소 2009 Journal of Ceramic Processing Research Vol.10 No.1

The properties of green and reaction-bonded SiC (RBSC) samples prepared by a gelcasting technique are investigated in this paper. The results show that solid loading and monomer content of the suspension in the gelcasting process are the main factors that effect the density and shrinkage of the green bodies. A slurry with a solid loading of 58 vol% was solidified in situ to a green body with a linear shrinkage of 1.1% and flexural strength of 27 ± 2 MPa. SEM micrographs show that the SiC and C particles in the green body were closely compact by a connection of the polymer network. The maximum density and flexural strength of samples reaction sintered at 1700℃ in vacuum were 2.97 g/㎤ and 378 ± 12 MPa respectively. The properties of green and reaction-bonded SiC (RBSC) samples prepared by a gelcasting technique are investigated in this paper. The results show that solid loading and monomer content of the suspension in the gelcasting process are the main factors that effect the density and shrinkage of the green bodies. A slurry with a solid loading of 58 vol% was solidified in situ to a green body with a linear shrinkage of 1.1% and flexural strength of 27 ± 2 MPa. SEM micrographs show that the SiC and C particles in the green body were closely compact by a connection of the polymer network. The maximum density and flexural strength of samples reaction sintered at 1700℃ in vacuum were 2.97 g/㎤ and 378 ± 12 MPa respectively.

Seismic performance of steel columns corroded in general atmosphere

Youde Wang,Tao Shi,Biao Nie,Hao Wang,Shanhua Xu 국제구조공학회 2021 Steel and Composite Structures, An International J Vol.40 No.2

Steel structures exposed to general atmosphere for a long time are highly susceptible to corrosion damage, which would lead to the degradation of service performance of the components and even structures. This article focuses on the effect of corrosion on the seismic performance of steel column. The accelerated corrosion tests in general atmosphere were conducted on 7 H-shaped steel columns and 20 steel plates. Then the obtained plate specimens were subjected to monotonic tensile tests and cyclic loading tests, and the steel columns were subjected to pseudo-static tests, respectively, to study the effects of corrosion on their mechanical properties and seismic performance. Then, a simplified three-dimensional finite element model (FEM) capable of accurately simulating the hysteretic response of corroded steel columns under low-cycle loading was established. Experimental results indicated that the yield strength, tensile strength, elastic modulus and peak strain of corroded steel plate decreased linearly with the proposed corrosion damage parameter Dn, and the energy dissipations under low-cycle loading were significantly reduced. There is a correlation between the cyclic hardening parameters of corroded steel and the yield-tensile strength difference (SD), and then a simplified formula was proposed. Corrosion could result in the premature entrance of each loading stage of corroded columns and the deterioration of buckling deformation range, bearing capacity and energy dissipation, etc. In addition, a larger axial compression ratio (CR) would further accelerate the failure process of corroded columns. The parametric finite element analysis (FEA) indicated that greater damage was found for steel columns with non-uniform corrosion, and hysteretic performance degraded more significantly when corrosion distributed at flanges or foot zone.

PtPd/molecular sieve as dual-functional monolithic adsorbent/catalyst for effective removal of trace toluene at low-temperature and their electric-heating performance

Shuangde Li,Tao Wang,Mu Zhou,Shaohua Chai,Linfeng Nie,Zhenjiang Wu,Ning Han,Yunfa Chen 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.114 No.-

A dual-functional adsorption–catalytic system for elimination of trace toluene is developed and realizedover molecular sieve-hosted varied ratio of platinum and palladium catalysts. PtPd/molecular sieveexhibites PdO and PtO2 around 2–3 nm particles with uniform loading verified by XRD, TEM, Ramanand XPS. The adsorption–desorption–catalysis for trace toluene purification is evaluated on the quartzmicro-reactor and the self-made electrically heated equipment. 3Pt1Pd/molecular sieve shows tolueneadsorption capacity of 18.22 mg/g and desorption efficiency about 77%, together with the maximum desorptiontemperature at 100 C. 3Pt1Pd/molecular sieve owns toluene conversion with 38.3% and 100% at100 and 200 C, accompanied with the higher CO2 selectivity of 0.0% and 150.0%, separately, due to thehigher Pd2+ content. The catalyst displays water vapor endurance, reproducibility, and 83.0% carbon balanceduring the whole adsorption–desorption–catalysis within 150 min, which highlights the sustainableapplicability in lean VOCs abatement. Furthermore, the possible catalytic reaction pathway of tolueneoxidation is proposed based on the in-situ DRIFTS experiments.

Adipose-Derived Stem Cell Transplantation Inhibits Vascular Inflammatory Responses and Endothelial Dysfunction in Rats with Atherosclerosis

Mingqiang Fan,Jing Bai,Tao Ding,Xiangxiang Yang,Qiaoke Si,Dengmei Nie 연세대학교의과대학 2019 Yonsei medical journal Vol.60 No.11

Purpose: This study aimed to investigate the effect of adipose-derived stem cell (ADSC) transplantation on atherosclerosis (AS)and its underlying mechanisms. Materials and Methods: In our study, rat AS model was established, and ADSCs were isolated and cultured. Atheroscleroticplaque and pathological symptoms of thoracic aorta were measured by Oil Red O staining and Hematoxylin-Eosin staining, respectively. Total cholesterol (TC), triglyceride (TG), high-density lipoprotein cholesterol (HDL-C), and low-density lipoproteincholesterol (LDL-C) levels were measured by an automatic biochemical analyzer. Expressions of vascular endothelial growth factor(VEGF), vascular cell adhesion molecule-1 (VCAM-1), intercellular adhesion molecule-1 (ICAM-1), aortic endothelin-1 (ET-1), interleukin-6 (IL-6), c-reactive protein (CRP), and tumor necrosis factor α (TNF-α) were measured by enzyme linked immunosorbentassay, VEGF, VCAM-1, ICAM-1, ET-1, respectively, and NF-κB p65 mRNA expressions were detected by quantitative realtimepolymerase chain reaction. Protein expressions of VEGF, VCAM-1, ICAM-1, ET-1, NF-κB p65, p-NF-κB p65, and IκBα weremeasured by western blot. Moreover, NF-κB p65 expression was measured by immunofluorescence staining. Results: ADSC transplantation alleviated the pathological symptoms of aortic AS. ADSC transplantation decreased the levels ofTC, TG, and LDL-C and increased serum HDL-C level. Meanwhile, ADSC transplantation decreased the levels of IL-6, CRP, andTNF-α in AS rats. Moreover, the expressions of VEGF, ET-1, VCAM-1, and ICAM-1 were decreased by ADSC transplantation. ADSC transplantation inhibited phosphorylation of NF-κB p65 and promoted IκBα expression in AS rats. Conclusion: Our study demonstrated that ADSC transplantation could inhibit vascular inflammatory responses and endothelialdysfunction by suppressing NF-κB pathway in AS rats.

Cenozoic tectonic evolution in the western Qaidam Basin inferred from subsurface data

Yadong Wang,Junsheng Nie,Tao Zhang,Guoqiang Sun,Xin Yang,Yuhu Liu,Xingwang Liu 한국지질과학협의회 2010 Geosciences Journal Vol.14 No.4

It is an agreement that collision of Indian and Asian plates causes uplift of the Tibet Plateau. However, great controversy exists about uplifting history and mechanisms of the Tibetan Plateau. Uplift history of the Tibetan Plateau has been well recorded in the Qaidam Basin, located in the northern margin of the Tibet Plateau. In this paper, we recognize and classify faults recorded by subsurface seismic data in the western Qaidam Basin. In addition, we reconstruct the Cenozoic deformation history of the Qaidam Basin based on balanced section of 5 seismic profiles. The results indicates that 1) Faults in the western Qaidam Basin can be classified as growth faults and non-growth faults, and the growth faults could be divided into three subcategories. 2) According to timing and manner of fault activities, faults and strata in the western Qaidam Basin could be divided into two structural layers: the lower (Lulehe Fm-Xia Youshashan Fm) and the upper (Shang Youshashan Fm-Qigequan Fm) layer. 3) The western Qaidam Basin has experienced two intensive tectonic deformations: the first phase occurs at 43.8−22 Ma (Middle Eocene−Early Miocene), which reached peak at 31.5 Ma (Early Oligocene); the second phase occurred between 14.9 and 0 Ma (Middle Miocene−Present), and the second phase is stronger than the first phase. Recognizing early fault activities confirm previous results that northern Tibet has sensed collision between the India and the Asia shortly after the collision. However, our results here emphasize that the northern Tibet has experienced another phase of shortening and uplift in the late Neogene. It was the two-stage tectonic activities that work together to produce the current Tibetan Plateau.

Clenbuterol Inhibits SREBP-1c Expression by Activating CREB1

Zhou, Lei,Li, Yixing,Nie, Tao,Feng, Shengqiu,Yuan, Jihong,Chen, Huaping,Yang, Zaiqing Korean Society for Biochemistry and Molecular Biol 2007 Journal of biochemistry and molecular biology Vol.40 No.4

As a $\beta_2$-adrenergic agonist, clenbuterol decreases body fat, but the molecular mechanism underlying this process is unclear. In the present study, we treated 293T and L-02 cells with clenbuterol and found that clenbuterol downregulates SREBP-1c expression and upregulates CREB1 expression. Considering SREBP-1c has the function of regulating the transcription of several lipogenic enzymes, we considered that the downregulation of SREBP-1c is responsible for body fat reduction by clenbuterol. Many previous studies have found that clenbuterol markedly increases intracellular cAMP levels, therefore, we also investigated whether CREB1 is involved in this process. The data from our experiments indicate that CREB1 overexpression inhibits SREBP-1c transcription, and that this action is antagonized by CREB2, a competitive inhibitor of CREB1. Furthermore, since PPARs are able to repress SREBP-1c transcription, we investigated whether clenbuterol and CREB1 function via a pathway involving PPAR activation. However, our results showed that clenbuterol or CREB1 overexpression suppressed PPARs transcription in 293T and L-02 cells, which suggested that they impair SREBP-1c expression in other ways.

Effects of fission product doping on the structure, electronic structure, mechanical and thermodynamic properties of uranium monocarbide: A first-principles study

Ru-Ting Liang,Tao Bo,Wan-Qiu Yin,Chang-Ming Nie,Lei Zhang,Zhi-Fang Chai,Wei-Qun Shi Korean Nuclear Society 2023 Nuclear Engineering and Technology Vol.55 No.7

A first-principle approach within the framework of density functional theory was employed to study the effect of vacancy defects and fission products (FPs) doping on the mechanical, electronic, and thermodynamic properties of uranium monocarbide (UC). Firstly, the calculated vacancy formation energies confirm that the C vacancy is more stable than the U vacancy. The solution energies indicate that FPs prefer to occupying in U site rather than in C site. Zr, Mo, Th, and Pu atoms tend to directly replace U atom and dissolve into the UC lattice. Besides, the results of the mechanical properties show that U vacancy reduces the compressive and deformation resistance of UC while C vacancy has little effect. The doping of all FPs except He has a repairing effect on the mechanical properties of U_1-xC. In addition, significant modifications are observed in the phonon dispersion curves and partial phonon density of states (PhDOS) of UC_1-x, Zr_xU_1-xC, Mo_xU_1-xC, and Rh_xU_1-xC, including narrow frequency gaps and overlapping phonon modes, which increase the phonon scattering and lead to deterioration of thermal expansion coefficient (α_V) and heat capacity (C_p) of UC predicted by the quasi harmonic approximation (QHA) method.