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Fulin Wen,Jianhua Zhao,Kaiqing Feng,Miaowang Yuan,Dengzhi Zheng,Cheng Gu,Bei Xu 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.7
In this paper, TC4/AZ91D bimetallic composites has been prepared by liquid–solid compound casting process adaptingvarious thickness of Cu coating. The effects of Cu coating thickness on the evolution of interface microstructures and jointmechanical properties are investigated. The results indicate that metallurgical bonded joints are obtained with Cu coatingthickness ranging from 36.7 to 51.4 μm. With the increase of Cu coating thickness, the interface microstructure evolvesfrom δ-Mg + Mg2Cueutectic structure to Mg–Cu intermetallic compound (IMC) Cu2Mg+ Mg2Cuand Mg–Al–Cu ternaryintermetallic compound. The calculation results of formation enthalpy and chemical potential of Mg–Al–Cu system suggestthat Cu element prefers to react with Mg element and formed Mg–Cu IMC. In particular, when Cu coating thickness reaches36.7 μm, the average shear strength of the bimetal reaches a maximum of 65.3 MPa. Further increasing Cu coating thicknessleads to the generation of thick Mg2CuIMC layer and Mg2Cu+ Cu2Mgmixed IMC layer which are proved to be harmful tothe shear strength of TC4/AZ91D bimetals. All the fracture surfaces of the bimetallic composites exhibite to have a brittlefracture morphology. However, the fracture location is different with each other. For Cu coating thickness of 36.7 μm, theinterface fractures at the δ-Mg + Mg2Cueutectic structure, while the interface fractures at the Cu2Mg+ Mg–Al–Cu ternaryintermetallic layers when Cu coating thickness is 44.2 μm and 51.4 μm.
Fulin Wang,Qi Tao,Luoqiong Xiao,Jiahao Hu,Leilei Xu 대한기계학회 2018 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.32 No.5
A realistic finite element model considering the ploughing effect of cutting edge fillet was developed in high speed machining. Taking the hardened tool steel AISI D2 as the object of research, the cutting force and chip morphology were reasonably analyzed and compared with the actual results of cutting experiments, which verified the correctness of the model. Then, based on the model, the formation process of single serrated tooth was analyzed, while the effects of cutting heat and temperature field, material hardness and cutting speed on chip formation were explored. The research results indicate that: (1) The ploughing-effect has a great impact on the feed force, and for hardened tool steel AISI D2, the stagnation angle of 30 o is more appropriate. (2) Also, stress concentration appears and shear slipping occurs along the shear plane in the process of serrated chip formation. The strain rate on the shear slipping surface is much greater than other places and the temperature gradient perpendicular to the shear plane is relatively higher. (3) The cutting force becomes larger with increasing the hardness value of workpieces, which causes the chip to more likely to produce serrated chips. (4) The fluctuation of cutting force is more significant as the cutting speed increases, which puts forward higher requirements for the tool and machine tool.
Heat transfer characteristics in regenerator cell for gaseous organic compound treatment
Fulin Liu,Kaiming Ren,Junyan Pei,Xuze Zhao,Xiaowen Hao 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.2
Regenerative combustion technology can efficiently decompose organic gases with high thermal efficiency. This capability is attributed to the regenerator and the periodic gas switching technology. However, published findings regarding the regenerator were inconsistent with some important parameters, and investigations into the regenerative chamber did not provide a comprehensive explanation of the heat transfer characteristics. Therefore, a regenerator cell was investigated in this study. The temperature distribution pattern inside the cell was simulated after model verification. The effects of the superficial velocity, switching time, side width, and wall thickness of the regenerator cell on the outlet temperature, energy recovery ratio, and heat-transfer coefficient were investigated. The outlet temperature, heat transfer, and energy recovery ratio of the regenerator cells varied monotonically during each period. The average energy recovery ratio and heat transfer coefficient indicated that the side width of the regenerator cell was the most significant factor. Meanwhile, the switching time and wall thickness did not significantly affect the energy recovery ratio. The superficial velocity and wall thickness did not significantly affect the heat transfer coefficient.
Fulin Tao,Yuanyuan Zhou,Mengwen Wang,Chongyang Wang,Wentao Zhu,Zhili Han,Nianxia Sun,Dianlei Wang 대한약리학회 2022 The Korean Journal of Physiology & Pharmacology Vol.26 No.2
Chronic obstructive pulmonary disease (COPD) is an important healthcare problem worldwide. Often, glucocorticoid (GC) resistance develops during COPD treatment. As a classic hypoglycemic drug, metformin (MET) can be used as a treatment strategy for COPD due to its anti-inflammatory and antioxidant effects, but its specific mechanism of action is not known. We aimed to clarify the role of MET on COPD and cigarette smoke extract (CSE)-induced GC resistance. Through establishment of a COPD model in rats, we found that MET could improve lung function, reduce pathological injury, as well as reduce the level of inflammation and oxidative stress in COPD, and upregulate expression of nuclear factor E2-related factor 2 (Nrf2), heme oxygenase-1 (HO-1), multidrug resistance protein 1 (MRP1), and histone deacetylase 2 (HDAC2). By establishing a model of GC resistance in human bronchial epithelial cells stimulated by CSE, we found that MET reduced secretion of interleukin- 8, and could upregulate expression of Nrf2, HO-1, MRP1, and HDAC2. MET could also increase the inhibition of MRP1 efflux by MK571 significantly, and increase expression of HDAC2 mRNA and protein. In conclusion, MET may upregulate MRP1 expression by activating the Nrf2/HO-1 signaling pathway, and then regulate expression of HDAC2 protein to reduce GC resistance
Solidification of uranium tailings using alkali-activated slag mixed with natural zeolite
Wang Fulin,Zhou Min,Chen Cheng,Yuan Zhengping,Geng Xinyang,Yang Shijiao 한국원자력학회 2023 Nuclear Engineering and Technology Vol.55 No.2
Cemented uranium tailings backfill created from alkali-activated slag (CUTB) is an effective method of disposing of uranium tailings. Using some environmental functional minerals with ion exchange, adsorption, and solidification abilities as backfill modified materials may improve the leaching resistance of the CUTB. Natural zeolite, which has good ion exchange and adsorption characteristics, is selected as the backfill modified material, and it is added to the backfill materials with cementitious material proportions of 4%, 8%, 12%, and 16% to prepare CUTB mixtures with environmental functional minerals. After the addition of natural zeolite, the uniaxial compressive strength (UCS) of the CUTB decreases, but the leaching resistance of the CUTB increases. When the natural zeolite content is 12%, the UCS reaches the minimum value of 8.95 MPa, and the concentration of uranium in the leaching solution is 0.28e8.07 mg/L, the leaching rate R42 is 9.61 107 cm/d, and cumulative leaching fraction P42 is 8.53 104 cm, which shows that the alkali-activated slag cementitious material has a good curing effect on the CUTB, and the addition of environmental functional minerals helps to further improve the leaching resistance of the CUTB, but it reduces the UCS to an extent.
Xiong, Jinfei,Zhou, Fulin,Li, Qunzhan The Korean Institute of Power Electronics 2021 JOURNAL OF POWER ELECTRONICS Vol.21 No.7
Cascaded H-bridge inverters with separated DC sources charging the DC-link are widely used in the industry application due to its inherent advantages. However, a failure of the DC sources can interrupt the power supply which results in economic loss. This paper proposes a soft-switching modulation algorithm to tackle this issue. A pre-set table lists all of the possible redundant module states that can adjust the voltage of the DC-link. With this method, the DC voltages can be always balanced even under DC source failures, resulting in good flexibility, good dynamic performance and no voltage level-skip. Hence, a reliable and continuous power supply is guaranteed. Finally, 3-module experimental results verify the validity of the proposed method and simulation tests are used to verify its balance limitations.
Guo-Qiang Li,Fulin Gu,Jian Jiang,Feifei Sun 국제구조공학회 2017 Steel and Composite Structures, An International J Vol.23 No.4
This paper experimentally studies the cyclic behavior of hybrid connections between steel coupling beams and concrete shear walls with embedded steel columns. Four beam-to-wall connection specimens with short and long embedded steel columns are tested under monotonic and cyclic loads, respectively. The influence of embedment length of columns on the failure mode and performance of connections is investigated. The results show that the length of embedded steel columns has significant effect on the failure mode of connections. A connection with a long embedded column has a better stiffness, loadbearing capacity and ductility than that of a short embedded column. The former fails due to the shear yielding of column web in the joint panel, while failure of the latter is initiated by the yielding of horizontal reinforcement in the wall due to the rigid rotation of the column. It is recommended that embedded steel columns should be placed along the entire height of shear walls to facilitate construction and enhance the ductility.