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4篇 您的检索式:作者名="DONG Jingjin"
    题名 作者 年代 出处 被引量
1Transient tribo-dynamic analysis of crosshead slipper in lowspeed marine diesel engines during engine startup显示文摘A crosshead slipper-guide system,which bears a significant thrust force,is an essential friction pair in low-speed marine diesel engines.Owing to the low moving speed of the crosshead slipper during engine startup,it is difficult to form good hydrodynamic lubrication between the crosshead slipper and guide.Therefore,a detailed analysis of the crosshead slipper during engine startup is needed.In this study,a new transient tribo-dynamic model for a crosshead slipper during the engine startup process is presented.The model consists of a mixed lubrication model of the crosshead slipper-guide and dynamic models of the piston assembly,crosshead assembly,connecting rod,and crankshaft.The tribo-dynamic performances of the crosshead slipper during startup and under the rated conditions were simulated and compared.The results show that the tribo-dynamics of the crosshead slipper during the startup process are significantly different from those under the rated conditions.Some measures beneficial for the low friction of a crosshead slipper-guide under the rated conditions may significantly increase the friction loss of the crosshead slipper-guide system during the startup process.Rui LI Xianghui MENG Jingjin DONG Wenda LI 2021Friction2021,9,6:2
2Long non-coding RNA HCAR promotes endochondral bone repair by upregulating VEGF and MMP13 in hypertrophic chondrocyte through sponging miR-15b-5p显示文摘Endochondral bone formation is an important route for bone repair.Although emerging evidence has revealed the functions of long non-coding RNAs(lncRNAs)in bone and cartilage development,the effect of lncRNAs in endochondral bone repair is still largely unknown.Here,we identified a lncRNA,named Hypertrophic Chondrocyte Angiogenesis-related lncRNA(HCAR),and proved it to promote the endochondral bone repair by upregulating the expression of matrix metallopeptidase 13(Mmp13)and vascular endothelial growth factorα(Vegfa)in hypertrophic chondrocytes.Lnc-HCAR knockdown in hypertrophic chondrocytes restrained the cartilage matrix remodeling and decrease the CD31hiEmcnhi vessels number in a bone repair model.Mechanistically,we proved that lnc-HCAR was mainly enriched in the cytoplasm using fluorescence in situ hybridization(FISH)assay,and it acted as a molecular sponge for miR-15b-5p.Further,in hypertrophic chondrocytes,lnc-HCAR competitively bound to miR-15b-5p to increase Vegfa and Mmp13 expression.Our results proved that lncRNA is deeply involved in endochondral bone repair,which will provide a new theoretical basis for future strategies for promoting fracture healing.Yun Bai Xiaoshan Gong Rui Dong Zhen Cao Ce Dou Chuan Liu Jianmei Li Fei Kang Jingjin Dai Chunrong Zhao Zhansone Tian Jiulin Tan Qijie Dai Shiwu Dong 2022Genes & Diseases2022,9,2:1
3A Numerical Investigation on the Effects of Intake Swirl and Mixture Stratification on Combustion Characteristics in a Natural-Gas/Diesel Dual-Fuel Marine Engine显示文摘Natural gas/diesel dual-fuel combustion strategy has a great potential to reduce emissions for marine engines while the high fuel consumption is the major problem.Pre-chamber system is commonly employed as the ignition system on large-bore dual-fuel marine engines especially under lean-burn condition,due to its advanced ignition stability and engine efficiency.However,the ignition and combustion mechanism in such dual-fuel pre-chamber engine is still unclear and the effects of in-cylinder swirl flow and mixture stratification on combustion require further investigation specifically.This paper numerically studied the detailed ignition mechanism and combustion process in a marine engine equipped with a pre-chamber ignition system,and revealed the flame development process in main chamber.Moreover,the effects of mixture stratification and swirl ratio on the combustion rate and further engine thermal efficiency are investigated under decoupled condition.The results mainly show that the jet flame develops along the pre-chamber orifice centerline at the initial stage and premixed combustion play an important role,while after that,heat release zone only exist at flame surface,and premixed flame propagation controls the combustion process.In addition,with higher swirl ratio the combustion rate increases significantly due to the wider ignition area.Mixture stratification degree plays a role in accelerating the combustion,either too high or too low stratification degree reduce the combustion rate,while a moderate stratification increases the combustion rate.And appropriate stratification degree by verifying the gas injection parameters can reduce fuel consumption in 0.3%.YE Ying LIU Haifeng LI Jingrui LIU Teng DONG Jingjin LIU Bo WU Chaohui YUE Zongyu YAO Mingfa 2023Journal of Thermal Science2023,32,1:0
4Engineering the Thermoelectrical Properties of PEDOT:PSS by Alkali Metal Ion Effect显示文摘Engineering the electrical properties of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate)(PEDOT:PSS)holds great potential for various applications such as sensors,thermoelectric(TE)generators,and hole transport layers in solar cells.Various strategies have been applied to achieve optimal electrical properties,including base solution post-treatments.However,the working mechanism and the exact details of the structural transformations induced by base post-treatments are still unclear.In this work,we present a comparative study on the post-treatment effects of using three common and green alkali base solutions:namely LiOH,NaOH,and KOH.The structural modifications induced in the film by the base post-treatments are studied by techniques including atomic force microscopy,grazing-incidence wide-angle X-ray scattering,ultraviolet–visible–near-infrared spectroscopy,and attenuated total reflectance Fourier-transform infrared spectroscopy.Base-induced structural modifications are responsible for an improvement in the TE power factor of the films,which depends on the basic solution used.The results are explained on the basis of the different affinity between the alkali cations and the PSS chains,which determines PEDOT dedoping.The results presented here shed light on the structural reorganization occurring in PEDOT:PSS when exposed to high-pH solutions and may serve as inspiration to create future pH-/ion-responsive devices for various applications.Jingjin Dong Jian Liu Xinkai Qiu Ryan Chiechi L.Jan Anton Koster Giuseppe Portale 2021Engineering2021,7,5:0
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