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| 1 | A Multiscale Understanding of the Thermodynamic and Kinetic Mechanisms of Laser Additive Manufacturing显示文摘 | Dongdong Gu Chenglong Ma Mujian Xia Donghua Dai Qimin Shi | 2017 | Engineering2017，3，5： | 15 |
| 2 | Selective laser melting 3D printing of Ni-based superalloy: understanding thermodynamic mechanisms显示文摘A mesoscopic model has been established to investigate the thermodynamic mechanisms and densification behavior of nickel-based superalloy during additive manufacturing/three-dimensional(3D) printing(AM/3DP)by numerical simulation, using a finite volume method(FVM). The influence of the applied linear energy density(LED) on dimensions of the molten pool, thermodynamic mechanisms within the pool, bubbles migration and resultant densification behavior of AM/3DP-processed superalloy has been discussed. It reveals that the center of the molten pool slightly shifts with a lagging of 4 lm towards the center of the moving laser beam. The Marangoni convection, which has various flow patterns, plays a crucial role in intensifying the convective heat and mass transfer, which is responsible for the bubbles migration and densification behavior of AM/3DP-processed parts. At an optimized LED of 221.5 J/m, the outward convection favors the numerous bubbles to escape from the molten pool easily and the resultant considerably high relative density of 98.9 % is achieved. However, as the applied LED further increases over 249.5 J/m, the convection pattern is apparently intensified with the formation of vortexes and the bubbles tend to be entrapped by the rotating flow within the molten pool, resulting in a large amount of residual porosity and a sharp reduction in densification of the superalloy. The change rules of the relative density and the corresponding distribution of porosity obtained by experiments are in accordance with the simulation results. | Mujian Xia Dongdong Gu Guanqun Yu Donghua Dai Hongyu Chen Qimin Shi | 2016 | Science Bulletin2016，61，13： | 13 |
| 3 | Estimation of the Maximum Allowable Loading Amount of COD in Luoyuan Bay by a 3-D COD Transport and Transformation Model显示文摘The rapid economic and social developments in the Luoyuan and Lianjiang counties of Fujian Province, China, raise certain environment and ecosystem issues. The unusual phytoplankton bloom and eutrophication, for example, have increased in severity in Luoyuan Bay(LB). The constant increase of nutrient loads has largely caused the environmental degradation in LB. Several countermeasures have been implemented to solve these environmental problems. The most effective of these strategies is the reduction of pollutant loadings into the sea in accordance with total pollutant load control(TPLC) plans. A combined three-dimensional hydrodynamic transport-transformation model was constructed to estimate the marine environmental capacity of chemical oxygen demand(COD). The allowed maximum loadings for each discharge unit in LB were calculated with applicable simulation results. The simulation results indicated that the environmental capacity of COD is approximately 11×104 t year-1 when the water quality complies with the marine functional zoning standards for LB. A pollutant reduction scheme to diminish the present levels of mariculture- and domestic-based COD loadings is based on the estimated marine COD environmental capacity. The obtained values imply that the LB waters could comply with the targeted water quality criteria. To meet the revised marine functional zoning standards, discharge loadings from discharge units 1 and 11 should be reduced to 996 and 3236 t year-1, respectively. | WU Jialin LI Keqiang SHI Xiaoyong LIANG Shengkang HAN Xiurong MA Qimin WANG Xiulin | 2014 | Journal of Ocean University of China2014，13，4： | 1 |
| 4 | In-situ formation of Ti-Mo biomaterials by selective laser melting of Ti/Mo and Ti/Mo_(2)C powder mixtures:A comparative study on microstructure,mechanical and wear performance,and thermal mechanisms显示文摘Ti-Mo alloys/composites are expected to be the next-generation implant material with low moduli but without toxic/allergic elements.However,synthesis mechanisms of the Ti-Mo biomaterials in Selective Laser Melting(SLM)vary according to raw materials and fundamentally influence material performance,due to inhomogeneous chemical compositions and stability.Therefore,this work provides a comparative study on microstructure,mechanical and wear performance,and underlying thermal mechanisms of two promising Ti-Mo biomaterials prepared by SLM but through different synthesis mechanisms to offer scientific understanding for creation of ideal metal implants.They are(i)Ti-7.5 Mo alloys,prepared from a conventional Ti/Mo powder mixture,and(ii)Ti-7.5 Mo-2.4 Ti C composites,in-situ prepared from Ti/Mo_(2)C powder mixture.Results reveal that the in-situ Ti-7.5 Mo-2.4 Ti C composites made from Ti/Mo_(2)C powder mixture by SLM can produce 61.4%moreβphase and extra Ti C precipitates(diameter below 229.6 nm)than the Ti-7.5 Mo alloys.The fine Ti C not only contributes to thinner and shorterβcolumnar grains under a large temperature gradient of 51.2 K/μm but also benefits material performance.The in-situ Ti-7.5 Mo-2.4 Ti C composites produce higher yield strength(980.1±29.8 MPa)and ultimate compressive strength(1561.4±39 MPa)than the Ti-7.5 Mo alloys,increasing by up to 12.1%.However,the fine Ti C with an aspect ratio of 2.71 dominates an unfavourable rise of elastic modulus to 91.9±2 GPa,44.7%higher than the Ti-7.5 Mo alloys,which,nevertheless,is still lower than the modulus of traditional Ti-6 Al-4 V.While,Ti C and its homogeneous distribution benefit wear resistance,decreasing the wear rate of the in-situ Ti-7.5 Mo-2.4 Ti C composites to 6.98×10^(-4)mm^3 N^(-1)m^(-1),which is 36%lower than that of the Ti-7.5 Mo alloys.Therefore,although with higher modulus than the Ti-7.5 Mo alloys,the SLM-fabricated in-situ Ti-7.5 Mo-2.4 Ti C composites can expect to provide good biomedical application potential in cases where combined good strength and wear resistance are required. | Qimin Shi Shoufeng Yang Yi Sun Yifei Gu Ben Mercelis Shengping Zhong Bart Van Meerbeek Constantinus Politis | 2022 | Journal of Materials Science & Technology2022，，20： | 0 |
| 5 | Targeting lncRNA16 by GalNAc-siRNA conjugates facilitates chemotherapeutic sensibilization via the HBB/NDUFAF5/ROS pathway显示文摘Chemoresistance is a significant barrier to effective cancer treatment.Potential mechanisms for chemoresistance include reactive oxygen species(ROS)accumulation and expression of chemoresistance-promoting genes.Here,we report a novel function of lncRNA16 in the inhibition of ROS generation and the progression of chemoresistance.By analyzing the serum levels of lncRNA16 in a cohort of 35 patients with non-small cell lung cancer(NSCLC)and paired serum samples pre-and post-treatment from 10 NSCLC patients receiving neoadjuvant platinum-based chemotherapy,performing immunohistochemistry(IHC)assays on 188 NSCLC tumor samples,using comprehensive identification of RNA-binding proteins by mass spectrometry(ChIRP-MS)assays,as well as RNA immunoprecipitation(RIP)and RNA pull-down analyses,we discovered that patients with increased serum levels of lncRNA16 exhibited a poor response to platinum-based chemotherapy.The expression of hemoglobin subunit beta(HBB)and NDUFAF5 significantly increases with the development of chemoresistance.LncRNA16 binds to HBB and promotes HBB accumulation by inhibiting autophagy.LncRNA16 can also inhibit ROS generation via the HBB/NDUFAF5 axis and function as a scaffold to facilitate the colocalization of HBB and NDUFAF5 in the mitochondria.Importantly,preclinical studies in mouse models of chemo-resistant NSCLC have suggested that lncRNA16 targeting by trivalent N-acetylgalactosamine(GalNAc)-conjugated siRNA restores chemosensitivity and results in tumor growth inhibition with no detectable toxicity in vivo.Overall,lncRNA16 is a promising therapeutic target for overcoming chemoresistance,and the combination of first-line platinum-based chemotherapy with lncRNA16 intervention can substantially enhance anti-tumor efficacy. | Yanfang Liu Yan Wang Bing Liu Wenzhong Liu Yuanyuan Ma Yiren Cao Shi Yan Panpan Zhang Lixin Zhou Qimin Zhan Nan Wu | 2024 | Science China(Life Sciences)2024，67，4： | 0 |
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