Tension–Shear Experimental Analysis and Fracture Models Calibration on Q235 Steel

Xiaogang Huang,Zhen Zhou,Yazhi Zhu,Dongping Zhu,Lu Lu 한국강구조학회 2018 International Journal of Steel Structures Vol.18 No.5

Tension–shear loading is a common loading condition in steel structures during the earthquake shaking. To study ductile fracture in structural steel under multiple stress states, experimental investigations on the diff erent fracture mechanisms in Chinese Q235 steel were conducted. Diff erent tension–shear loading conditions achieved by using six groups of inclined notch butterfl y confi gurations covering pure shear, tension–shear and pure tension cases. Numerical simulations were carried out for all the specimens to determine the stress and strain fi elds within the critical sections. Two tension–shear fracture models were calibrated based on the hybrid experimental–numerical procedure. The equivalent fracture strain obtained from the round bar under tensile loading was used for evaluating these two models. The results indicated that the tension–shear criterion as a function of the shear fracture parameter had better performance in predicting the fracture initiation of structural steel under diff erent loading conditions.

Analytical investigation on lateral load responses of self-centering walls with distributed vertical dampers

Xiaogang Huang,Zhen Zhou,Dongping Zhu 국제구조공학회 2019 Structural Engineering and Mechanics, An Int'l Jou Vol.72 No.3

Self-centering wall (SCW) is a resilient and sustainable structural system which incorporates unbonded posttensioning (PT) tendons to provide self-centering (SC) capacity along with supplementary dissipators to dissipate seismic energy. Hysteretic energy dissipators are usually placed at two sides of SCWs to facilitate ease of postearthquake examination and convenient replacement. To achieve a good prediction for the skeleton curve of the wall, this paper firstly developed an analytical investigation on lateral load responses of self-centering walls with distributed vertical dampers (VD-SCWs) using the concept of elastic theory. A simplified method for the calculation of limit state points is developed and validated by experimental results and can be used in the design of the system. Based on the analytical results, parametric analysis is conducted to investigate the influence of damper and tendon parameters on the performance of VD-SCWs. The results show that the proposed approach has a better prediction accuracy with less computational effects than the Perez method. As compared with previous experimental results, the proposed method achieves up to 60.1% additional accuracy at the effective linear limit (DLL) of SCWs. The base shear at point DLL is increased by 62.5% when the damper force is increased from 0kN to 80kN. The wall stiffness after point ELL is reduced by 69.5% when the tendon stiffness is reduced by 75.0%. The roof deformation at point LLP is reduced by 74.1% when the initial tendon stress is increased from 0.45fpu to 0.65fpu.

Enhanced photocatalytic capacity of ZnS–ZnO–Sm2O3 composites for the removal of dyes and antibiotics in visible light region

Xiaogang Zheng,Fuyan Kang,Congying Huang,Sihao Lv,JinYang Zhang,Hao Peng 한국공업화학회 2020 Journal of Industrial and Engineering Chemistry Vol.88 No.-

ZnS–ZnO–Sm2O3 (Zn–Sm–XY) composites were prepared via the high-temperature calcination of coreshellstructured ZnS@Sm2O3 for the enhanced photocatalytic degradation of dyes and antibiotics invisible light region. Effects of calcined temperature, Sm2O3 content, pH value, contaminantconcentration, and inorganic ions on the photocatalytic activity were investigated. Ternary Zn–Smcomposites exhibit the excellent photocatalytic activity for the visible light driven degradation oftetracycline hydrochloride. Among these composites, Zn–Sm–2B prepared via the heat-treatment ofZnS–Sm2O3 at 673 K shows the best photocatalytic activity for the removal of tetracycline hydrochloride. The enhanced photocatalytic activity of Zn–Sm–2B is also achieved for the visible light drivendegradation of methyl orange, methylene blue, and rhodamine B within 20 min. In addition, Zn–Sm–6Ccalcined from Zn–Sm–C at 1073 K as well as Zn–Sm–2B exhibits excellent photocatalytic activity. OH andO2radicals are vital for the enhanced photocatalytic activity of Zn–Sm–2B and Zn–Sm–2B in visiblelight region, respectively. The lattice defects, sulfur vacancies, and oxygen vacancies facilitate the efficientcharge transfer and the rapid separation of electron-hole pairs at the junction interface of Zn–Sm–2B.

MgO nanosheets with N-doped carbon coating for the efficient visible-light photocatalysis

Xiaogang Zheng,Ke Wang,Zhiping Huang,Yong Liu,Jing Wen,Hao Peng 한국공업화학회 2019 Journal of Industrial and Engineering Chemistry Vol.76 No.-

MgO nanosheets with N-doped carbon coating (MgO@N-C) were fabricated for the enhancedphotocatalytic degradation of dyes (methylene blue, methyl violet, and Rhodamine B) and antibiotics(ciprofloxacin and tetracycline hydrochloride) in visible light region. The effects of N-doping content,reactant concentration, pH value, and inorganic ions on the photocatalytic performance in degradation ofmethylene blue were investigated in this work. Narrow band gap energy and heterojunction interfaceendowed the extended light-harvesting capacity to visible light region and the efficient charge transfer,leading to the excellent photocatalytic activity and durability of MgO@N-C-3 with N-doping content of 1.52%.

Ferromagnetic order and spin-glass behavior in multi-metallic compound Ni1.125Co0.375[Fe(CN)6] . 6.8H2O

Haifu Huang,Lina Wei,Yun He,Xiaogang Li,Fupei Liang 한국물리학회 2009 Current Applied Physics Vol.9 No.5

Multi-metallic Prussian blue compound Ni1.125Co0.375[Fe(CN)6] . 6.8H2O has been synthesized. The Mössbauer spectroscopy at room temperature and IR spectra study revealed that the metal ions are bonded through cyanide ligand and the presence of low spin FeIII(S = 1/2) and high spin FeIII(S = 5/2) ions, as showed in these structure: FeIII(S = 1/2)-CN-(CoII/NiII)(96%) and FeIII(S = 5/2)-NC-(CoII/NiII) (4%). The Curie constant of C = 3.00 ㎤ K mol-1 and Weiss paramagnetic Curie temperature of θ = 16.43 K were observed in fitting according to Curie–Weiss law. These results indicate that there existed a ferromagnetic exchange interaction in the complexes. The observed value of coercive field (Hc) and remanent magnetization (Mr) at 4 K for the compound are 497 Oe and 1.03 Nβ. The presence of spin-glass behaviours in the compound is ascribed mainly to domain mobility or domain growth under different cooling conditions. Multi-metallic Prussian blue compound Ni1.125Co0.375[Fe(CN)6] . 6.8H2O has been synthesized. The Mössbauer spectroscopy at room temperature and IR spectra study revealed that the metal ions are bonded through cyanide ligand and the presence of low spin FeIII(S = 1/2) and high spin FeIII(S = 5/2) ions, as showed in these structure: FeIII(S = 1/2)-CN-(CoII/NiII)(96%) and FeIII(S = 5/2)-NC-(CoII/NiII) (4%). The Curie constant of C = 3.00 ㎤ K mol-1 and Weiss paramagnetic Curie temperature of θ = 16.43 K were observed in fitting according to Curie–Weiss law. These results indicate that there existed a ferromagnetic exchange interaction in the complexes. The observed value of coercive field (Hc) and remanent magnetization (Mr) at 4 K for the compound are 497 Oe and 1.03 Nβ. The presence of spin-glass behaviours in the compound is ascribed mainly to domain mobility or domain growth under different cooling conditions.

Electrochemical Properties of Supercapacitors Using Boron Nitrogen Double-Doped Carbon Nanotubes as Conductive Additive

Hao Hu,Xiaogang Sun,Wei Chen,Jie Wang,Xu Li,Yapan Huang,Chengcheng Wei,Guodong Liang 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2019 NANO Vol.14 No.7

Carbon nanotubes (CNTs) were doped by ammonium borate as the sources of nitrogen and boron. Under the protection of Ar gas, boron-nitrogen doped CNTs were prepared through nitriding and boronization at high temperature. It is a conductive additive. Then, the obtained CNTs were mixed with activated carbon (AC), SP, sodium dodecyl sulfate (SDS), and cellulose fiber to prepare electrodes. With all the materials, a symmetric electric double-layer supercapacitor (EDLC) was assembled. Next, the materials and electrodes were also characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The factors, chemical connections, and specific surface area of the CNTs were analyzed by X-ray energy spectrum analysis (EDS), X-ray photoelectron spectroscopy (XPS), as well as a specific surface area and porosimetry analyzer (BET). In addition, the electrochemical performances of electric double-layer capacitors were tested with the help of cyclic voltammetry, constant-current charging and discharging, and so on. From the results, we can make a conclusion, that is, both B and N atoms were added into the CNTs and formed bonds successfully with carbon atoms mutually. Besides, the specific surface area is about 1.5 times than that of the CNT. When the charge/discharge current density reaches 50 mA/g, we can find that the mass specific capacitance of the capacitor can run up to 32.19 F/g. Also, we observe that the maximum power density is close to 220 W/kg (700 mA/g), and the energy density can arrive 9.31 Wh/kg (50 mA/g). Based on the impedance test, the electrodes are characterized with low impedance. After 2000 cycles, the boron-nitrogen doped double-layer capacitors maintain a capacitance retention ratio of above 95%. Its power density can still achieve 220 W/kg when the energy density keeps at 3.46 Wh/kg. In other words, the electrochemical performance functions of the electric double-layer capacitors are enhanced while the CNTs serve as the electrodes.

Efficient solar-light photocatalytic H2 evolution of Mn0.5Cd0.5S coupling with S,N-codoped carbon

Hao Peng,Congying Huang,Xiaogang Zheng,Jing Wen 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.106 No.-

The low-cost and highly-efficient photocatalysts for solar-light induced water splitting had drawn greatattention to develop the renewable hydrogen economy. To enhance the solar-light driven H2 evolution ofMn0.5Cd0.5S, Mn0.5Cd0.5S was modified by S,N-codoped carbon (3-MCS/SN-C) via the in-situ sulfurizationat high temperature. In contrast with Mn0.5Cd0.5S (11.13 mmol g1 h1) and S-doped g-C3N4(0.35 mmol g1 h1), the optimal 3-MCS/SN-C with a mass ratio of Mn0.5Cd0.5S to S,N-codoped carbonof 1:3 exhibited the best H2 evolution rate of 27.58 mmol g1 h1 and an apparent quantum yield of27.43% at 400 nm. The photo-corrosion induced to the decreased H2 evolution capacity of 3-MCS/SN-Cfrom 131.13 to 126.52 mmol g1 after five cycles of 5 h. S,N-codoped carbon could efficiently capture visiblelight and absorb the photons, leading to the efficient transformation and separation of photogeneratedcarriers at the junction interface between Mn0.5Cd0.5S and S,N-codoped carbon.

Experimental and numerical studies on the frame-infill in-teraction in steel reinforced recycled concrete frames

Jian-yang Xue,Xiaogang Huang,Zheng Luo,Liang Gao 국제구조공학회 2016 Steel and Composite Structures, An International J Vol.20 No.6

Masonry infill has a significant effect on stiffness contribution, strength and ductility of masonry-infilled frames. These effects may cause damage of weak floor, torsional damage or short-column failure in structures. This article presents experiments of 1/2.5-scale steel reinforced recycled aggregates concrete (SRRC) frames. Three specimens, with different infill rates consisted of recycled concrete hollow bricks (RCB), were subjected to static cyclic loads. Test phenomena, hysteretic curves and stiffness degradation of the composite structure were analyzed. Furthermore, effects of axial load ratio, aspect ratio, infill thickness and steel ratio on the share of horizontal force supported by the frame and the infill were obtained in the numerical example.

Sandwich Structure Electrode as Advanced Performance Anode for Lithium-Ion Batteries

Wei Chengcheng,Sun Xiaogang,Liang Guodong,Huang Yapan,Hu Hao,Xu Yuhao 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2019 NANO Vol.14 No.10

In this work, a sandwich structure electrode was prepared by a simple vacuum filtration and rolling process. The SEM showed that the active materials were uniformly embedded in the pores of the three-dimensional conductive network of the carbon nanotube (CNTs) conductive paper. The contact interface area of active material and the conductive network significantly increased and the interface resistance was greatly reduced. The porous anode can accommodate the volume expansion of the silicon and effectively alleviated pressed during cycle. The electrode also exhibited good stability in cycles. Electrochemical tests showed that the first discharge specific capacity of the sandwich electrode reached 2330 mAh/g with a coulombic efficiency of 86%. After 500 cycles, the specific capacity was still maintained at 1512 mAh/g. At a large current density of 2 A/g, the specific capacity hold was 840 mAh/g compared with the copper foil electrode of 100 mAh/g.

Sensitivity of Tropical Cyclone Intensity and Structure to Vertical Resolution in WRF

Zhanhong Ma,Jianfang Fei,Xiaogang Huang,Xiaoping Cheng 한국기상학회 2012 Asia-Pacific Journal of Atmospheric Sciences Vol.48 No.1

In this paper the impacts of vertical resolution on the simulations of Typhoon Talim (2005) are examined using the Weather Research and Forecasting (WRF) model, with cumulus parameterization scheme representing the cumulus convection implicitly. It is shown that the tropical cyclone (TC) track has little sensitivity to vertical resolution, whereas the TC intensity and structure are highly sensitive to vertical resolution. It is partly determined by the sensitivity of the planetary boundary layer (and the surface layer) and the cumulus convection processes to vertical resolution. Increasing vertical resolution in the lower layer could strengthen the TC effectively. Increasing vertical resolution in the upper layer is also beneficial for the storm intensification, but to a lesser degree. In contrast, improving the midlevel resolution may cause the convergence of environmental air,which inhibits the TC intensification. The results also show that the impacts of vertical resolution on features of the TC structure, such as the tangential winds, secondary circulations and the evolution of the warm-core structure, are consistent with the impacts on the TC intensity. It is suggested that in the simulations of TCs, the vertical levels should be distributed properly rather than the more the better,with higher vertical resolution being expected both in the lower and upper layer, while the middle layer should not hold too many levels.