Comparative Study of the Influence of Various Melt-Treatment Methods on Hot Deformation Behavior of 3003 Al Alloy

Guiqing Chen,Gaosheng Fu,Hongling Chen,Wenduan Yan,Chaozeng Cheng,Zechang Zou 대한금속·재료학회 2012 METALS AND MATERIALS International Vol.18 No.1

3003 Al alloy samples with various metallurgical qualities were obtained by various melt-treatment methods and were deformed by isothermal compression in the deformation temperature range of 300 °C to 500°C at strain rates between 0.0l and 10.0 s −1with a Gleeble-1500 thermal simulator. The results show that there is a close relationship between melt-treatment and subsequent thermal deformation. The hot deformation acti-vation energy (Q) bears a linear relationship with the inclusion content (H) of 3003 Al alloy prepared by various melt-treatment methods, that is Q = 35.62 H + 171.58. The activation energy of the 3003 Al alloy prepared by the highly efficient melt-treatment is the lowest (174.62 kJ·mol −1), which is beneficial to the material hot plastic deformation. The critical strain of the 3003 Al alloy prepared by various melt-treatment methods is investigated through the work hardening rate. Finally, the critical conditions of the investigated alloy were determined to predict the occurrence of dynamic recrystallization.

Combined with finite element analysis of car seat safety performance improvement

Li Hongling,Dong Yude,Chen Changliang,Chen Chao 대한기계학회 2021 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.35 No.1

Neck injuries caused by low-speed rear-end collisions are a worldwide problem. The reasonable design of car seat can effectively prevent or reduce the passenger neck injuries. In this paper, the finite element analysis (FEA) and whiplash test are combined to optimize the seat structure parameters to enhance the safety. The whiplash test results of the existing car seats according to C-NCAP (2015) were matched with FEA, and the optimization scheme was developed by computer simulation. For the improvement of seat safety, the optimizations are applied to determine backrest stiffness, backrest rotational stiffness, headrest rotational stiffness and headrest stiffness. The retest results of optimized seat show that its safety performance is greatly improved. Furthermore, it shows that the combination of finite element analysis and whiplash test can optimize seat structure to improve safety performance.

Optimization of a Hot Deformation Process of the 3003 Aluminum Alloy by Processing Maps

Guiqing Chen,Gaosheng Fu,Hongling Chen,Chaozeng Cheng,Wenduan Yan,Shaoyi Lin 대한금속·재료학회 2012 METALS AND MATERIALS International Vol.18 No.5

Hot deformation behavior of the 3003 Al alloy was investigated by conducting hot compression tests at various temperatures (300-500 °C) and strain rates (0.0l-10.0 s−1). A constitutive equation was established to describe the flow behavior. The apparent activation energy of the 3003 Al alloy was determined to be 174.62 kJ·mol−1, which is higher than that for self-diffusion in pure Al (165 kJ·mol−1). Processing maps at a strain of 0.6 for hot working were developed on a dynamic materials model. The maps exhibit a flow instability domain at about 300-380 °C and 1.0-10.0 s−1. Dynamic recrystallization occurs extensively in the temperature range of 450-500 °C and at the strain rate of 10.0 s−1. The optimum parameters of hot working for the 3003 Al alloy are confined at 500 °C and 10.0 s−1with the highest efficiency (37%).

One-Pot Synthesis of Magnetic Cationic Adsorbent Modified with PDDA for Organic Phosphonates Removal

Junjie Chen,Yonggan Ju,Hongling Chen 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2019 NANO Vol.14 No.2

Fe3O4 nanoparticles coating with poly dimethyl diallyl ammonium chloride (Fe3O4/PDDA) as novel magnetic adsorbents were synthesized with chemical co-precipitation method to study the removal capacity of organic phosphonates from aqueous solution. The as-prepared magnetic absorbents were characterized for the morphology, material structure and surface properties by SEM, TEM, FT-IR, XRD, TGA and BET. HEDP was employed as a common organic phosphonate to investigate the adsorption performance. Substantial quaternary ammonium groups existing on the surface of Fe3O4/PDDA could enhance the absorption of HEDP with electrostatic attraction. In the optimum condition (4 mg adsorbent dosage, 11.0 pH, 36 mg/L HEDP solution and 120 min adsorption time), the maximum adsorption capacity (qm) for HEDP could reach 254.86 mg/g. The kinetic study revealed that the adsorption process followed the pseudo-second-order model. The adsorption isotherm fitted closely to the Freundlich model. The as-prepared magnetic adsorbents exhibited notable reusability in some cycles and were easily separated from the solution with the external magnetic field. These as-prepared Fe3O4/PDDA nanoparticles have the potential as an environmental-friendly adsorbent for organic phosphonates removal from waste-water.

Robust Super-Repellent Anisotropic Silica Films by Emulsion-Based Sol–Gel Growth

Yingyu Zhou,Hongling Chen 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2018 NANO Vol.13 No.1

In this paper, anisotropic SiO2 with different morphologies were synthesized through an emulsion-based one-pot method by adding various silane coupling agents. Silane coupling agents affected the growth of silica nanostructures at the oil/water interfaces. Robust super-repellent film that showed great durability under different harsh conditions were obtained by bonding the self-assembled anisotropic silica nanostructures (ASN) film to substrate by the commercial acrylic adhesive. The ¯lm switched from superhydrophobic (157.1°) to superhydrophilic (0°) after being heat-treated at 500 ℃. Further, silane treatment with addition of acid reduced the time of modification. Meanwhile, silane grafting density was improved and superhydrophobicity of calcinated ASN films was regenerated.

Boiling heat transfer-based temperature rise characteristics of automotive permanent magnet synchronous motors at peak operating conditions

He Liange,Chen Hongling,Shi Wenjun 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.7

Using two-phase flow boiling heat transfer theory, the RPI subcooling boiling heat transfer model was established to study the temperature rise characteristics of the permanent magnet synchronous motor (PMSM) of electric vehicles under peak operating conditions, and the effects of coolant inlet temperature, altitude and inlet flow rate on the motor temperature rise were analyzed. The results showed that: the temperature rise characteristics of the motor are closer to the test results when boiling heat transfer is considered after the motor is warmed up, so the effect of boiling heat transfer of the cooling system should be considered when studying the temperature rise characteristics of the motor; The temperature rise characteristic of the motor increases with the increase of coolant inlet temperature at peak working condition. The short time required for the motor winding to reach 150 °C indicates that the motor temperature rises quickly. In the plateau environment, the temperature growth rate of the motor at peak working conditions increases with the increase of cooling water inlet temperature, while the motor temperature decreases with the decrease of atmospheric pressure. Thus, due to the boiling heat transfer phenomenon of cooling water two-phase flow, the temperature rise characteristic of the motor at high altitude is better than that in plain area.

Tanshinone IIA Protects Endothelial Cells from H₂O₂-Induced Injuries via PXR Activation

Zhu, Haiyan,Chen, Zhiwu,Ma, Zengchun,Tan, Hongling,Xiao, Chengrong,Tang, Xianglin,Zhang, Boli,Wang, Yuguang,Gao, Yue The Korean Society of Applied Pharmacology 2017 Biomolecules & Therapeutics(구 응용약물학회지) Vol.25 No.6

Tanshinone IIA (Tan IIA) is a pharmacologically active substance extracted from the rhizome of Salvia miltiorrhiza Bunge (also known as the Chinese herb Danshen), and is widely used to treat atherosclerosis. The pregnane X receptor (PXR) is a nuclear receptor that is a key regulator of xenobiotic and endobiotic detoxification. Tan IIA is an efficacious PXR agonist that has a potential protective effect on endothelial injuries induced by xenobiotics and endobiotics via PXR activation. Previously numerous studies have demonstrated the possible effects of Tan IIA on human umbilical vein endothelial cells, but the further mechanism for its exerts the protective effect is not well established. To study the protective effects of Tan IIA against hydrogen peroxide ($H_2O_2$) in human umbilical vein endothelial cells (HUVECs), we pretreated cells with or without different concentrations of Tan IIA for 24 h, then exposed the cells to $400{\mu}M$ $H_2O_2$ for another 3 h. Therefore, our data strongly suggests that Tan IIA may lead to increased regeneration of glutathione (GSH) from the glutathione disulfide (GSSG) produced during the GSH peroxidase-catalyzed decomposition of $H_2O_2$ in HUVECs, and the PXR plays a significant role in this process. Tan IIA may also exert protective effects against $H_2O_2$-induced apoptosis through the mitochondrial apoptosis pathway associated with the participation of PXR. Tan IIA protected HUVECs from inflammatory mediators triggered by $H_2O_2$ via PXR activation. In conclusion, Tan IIA protected HUVECs against $H_2O_2$-induced cell injury through PXR-dependent mechanisms.

Erratum to Tanshinone IIA Protects Endothelial Cells from H₂O₂-Induced Injuries via PXR Activation [Biomol Ther 25(6), 599-608 (2017)]

( Haiyan Zhu ),( Zhiwu Chen ),( Zengchun Ma ),( Hongling Tan ),( Chengrong Xiao ),( Xianglin Tang ),( Boli Zhang ),( Yuguang Wang ),( Yue Gao ) 한국응용약물학회 2024 Biomolecules & Therapeutics(구 응용약물학회지) Vol.32 No.2

Preparation of ZnO@void@SiO2 Rattle Type Core–Shell Nanoparticles via Layer-by-Layer Method

Xiaoman Wang,Junda Song,Hongling Chen 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2016 NANO Vol.11 No.9

In this paper, we prepared the rattle type nanoparticles ZnO@void@SiO2 by two successive coating processes, followed by heat treatment. The carbon layer was formed over ZnO surface with the aid of the hydrothermal treatment of glucose. Then the resulting composite was used to fabricate a silica shell on the surface by sol–gel method. Finally, ZnO particles were released but still trapped inside the silica hollow after calcination, that is, ZnO@void@SiO2. The composites were characterized by scanning and transmission electron microscope, N2 adsorption experiment, X-ray diffraction, Fourier transform infrared spectroscopy and UV-Vis absorption spectra. The rattle type structure was conformed and the sphere-like structure with the average size of 70 nm and hexagonal wurtzite crystal structure were also observed. The measurement results of optical properties showed even though ZnO@C@SiO2 presented no photocatalysis, ZnO@void@SiO2 showed high activity even the ZnO core was encapsulated with the SiO2 hollow.

Tanshinone IIA Protects Endothelial Cells from H₂O₂-Induced Injuries via PXR Activation

( Haiyan Zhu ),( Zhiwu Chen ),( Zengchun Ma ),( Hongling Tan ),( Chengrong Xiao ),( Xianglin Tang ),( Boli Zhang ),( Yuguang Wang ),( Yue Gao ) 한국응용약물학회 2017 Biomolecules & Therapeutics(구 응용약물학회지) Vol.25 No.6

Tanshinone IIA (Tan IIA) is a pharmacologically active substance extracted from the rhizome of Salvia miltiorrhiza Bunge (also known as the Chinese herb Danshen), and is widely used to treat atherosclerosis. The pregnane X receptor (PXR) is a nuclear receptor that is a key regulator of xenobiotic and endobiotic detoxification. Tan IIA is an efficacious PXR agonist that has a potential protective effect on endothelial injuries induced by xenobiotics and endobiotics via PXR activation. Previously numerous studies have demonstrated the possible effects of Tan IIA on human umbilical vein endothelial cells, but the further mechanism for its exerts the protective effect is not well established. To study the protective effects of Tan IIA against hydrogen peroxide (H₂O₂) in human umbilical vein endothelial cells (HUVECs), we pretreated cells with or without different concentrations of Tan IIA for 24 h, then exposed the cells to 400 μM H₂O₂ for another 3 h. Therefore, our data strongly suggests that Tan IIA may lead to increased regeneration of glutathione (GSH) from the glutathione disulfide (GSSG) produced during the GSH peroxidase-catalyzed decomposition of H₂O₂ in HUVECs, and the PXR plays a significant role in this process. Tan IIA may also exert protective effects against H₂O₂-induced apoptosis through the mitochondrial apoptosis pathway associated with the participation of PXR. Tan IIA protected HUVECs from inflammatory mediators triggered by H₂O₂ via PXR activation. In conclusion, Tan IIA protected HUVECs against H₂O₂-induced cell injury through PXR-dependent mechanisms.