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| 1 | Pre-chamber turbulent jet ignition of methane/air mixtures with multiple orifices in a large bore constant volume chamber: effect of air-fuel equivalence ratio and pre-mixed pressure显示文摘Liquefied natural gas (LNG), mainly composed of methane, is in progress to substitute diesel fuel in heavyduty marine engine for practical, economic, and environmental considerations. However, natural gas is relatively difficult to be ignited in a large bore combustion chamber. A combustion enhancement technique called prechamber turbulent jet ignition (TJI) can permit combustion and flame propagation in a largebore volume. To investigate the effect of air-fuel equivalence ratio and pre-mixed pressure on pre-chamber TJI of methane/air mixtures with multiple orifices in a large bore volume, experimental tests and computational simulations were implemented to study the discharge of hot turbulent jets from six orifices of the pre-chamber. Different initial pressures and air-fuel equivalence ratios were considered to analyze the characteristics of TJI. The asymmetry of the turbulent jet actuated from six different orifices were found due to the asymmetric orientation of the spark plug, resulting in the inhomogeneous distribution of combustion in the constant volume chamber, which should be considered seriously in the marine engine design. Besides,as the premixed pressure increases, it has more effect on the flame propagation and plays a more important role, as it further increases. | Xiang LI Wenzheng ZHANG Zhong HUANG Dehao JU Li HUANG Mingzhi FENG Xingcai LU Zhen HUANG | 2019 | Frontiers in Energy2019，13，3： | 3 |
| 2 | Research on numerical simulation of transient pressure for high-speed train passing through the most unfavourable length tunnel显示文摘The length of high-speed railway tunnel is an important factor affecting transient pressure of high-speed train.When the tunnel length is the most unfavourable,the transient pressure changes in the tunnel and on the surface of the train are the most severe,which may affect the safe operation of the train or damage the structure in the tunnel.Based on the three-dimensional,compressible,unsteady N-S equation and finite volume method,this paper uses the CFD numerical simulation method to study the change and amplitude distribution of the transient pressure on the train surface and the tunnel when a high-speed train passes through the most unfavourable length tunnel.A fast calculation method is proposed to save the cost of calculation;it has great applicability of pressure amplitude.The results show that the pressure distribution in the tunnel and on the surface of the train is affected by the train speed,the length of the train and the position of the measuring point.The minimum negative peak value in the tunnel appears at the position where the superposition phenomenon is the most severe,and the position will change with the speed of the train.There are two negative peak waveforms of the train surface pressure,and the first waveformn is greatly affected by the train speed.It improves a reference for studying the strength requirement of the most unfavourable length tunnels and trains,and ensures the safe operation of trains in tunnels of different lengths. | Zhao Liu Feng Liu Shuanbao Yao Dawei Chen Mingzhi Yang | 2023 | Transportation Safety and Environment2023，5，3： | 1 |
| 3 | Profiling of miRNAs in porcine Sertoli cells显示文摘Background: Sertoli cells(SCs) create a specialized environment to support and dictate spermatogenesis.MicroRNAs(miRNAs), a kind of ~ 22 nt small noncoding RNAs, have been reported to be highly abundant in mouse SCs and play critical roles in spermatogenesis. However, the miRNAs of porcine SCs remain largely unknown.Methods: We isolated porcine SCs and conducted small RNA sequencing. By comparing miRNAs in germ cells, we systematically analyzed the miRNA expression pattern of porcine SCs. We screened the highly enriched SC miRNAs and predicted their functions by Gene Ontology analysis. The dual luciferase assay was used to elucidate the regulation of tumor necrosis factor receptor(TNFR)-associated factor 3(TRAF3) by ssc-miR-149.Results: The analysis showed that 18 miRNAs were highly expressed in SCs and 15 miRNAs were highly expressed in germ cells. These miRNAs were predicted to mediate SC and germ cell functions. In addition, ssc-miR-149 played critical roles in SCs by targeting TRAF3.Conclusion: Our findings provide novel insights into the miRNA expression pattern and their regulatory roles of porcine SCs. | Xiaoxu Chen Yi Zheng Xueliang Li Qiang Gao Tongying Feng Pengfei Zhang Mingzhi Liao Xiu’e Tian Hongzhao Lu Wenxian Zeng | 2021 | Journal of Animal Science and Biotechnology2021，12，1： | 1 |
| 4 | Over-Smoothing Algorithm and Its Application to GCN Semi-supervised Classification显示文摘The feature information of the local graph structure and the nodes may be over-smoothing due to the large number of encodings,which causes the node characterization to converge to one or several values.In other words,nodes from different clusters become difficult to distinguish,as two different classes of nodes with closer topological distance are more likely to belong to the same class and vice versa.To alleviate this problem,an over-smoothing algorithm is proposed,and a method of reweighted mechanism is applied to make the tradeoff of the information representation of nodes and neighborhoods more reasonable.By improving several propagation models,including Chebyshev polynomial kernel model and Laplace linear 1st Chebyshev kernel model,a new model named RWGCN based on different propagation kernels was proposed logically.The experiments show that satisfactory results are achieved on the semi-supervised classification task of graph type data. | Mingzhi Dai Weibin Guo Xiang Feng | 2020 | 国际计算机前沿大会会议论文集2020，，2： | 0 |
| 5 | Efficient and stable PtFe alloy catalyst for electrocatalytic methanol oxidation with high resistance to CO显示文摘Direct methanol fuel cells(DMFC) are widely considered to be an ideal green energy conversion device but their widespread applications are limited by the high price of the Pt-based catalysts and the instability in terms of surface CO toxicity in long-term operation.Herein,the PtFe alloy nanoparticles(NPs) with small particle size(~4.12 nm) supported on carbon black catalysts with different Pt/Fe atomic ratios(Pt_(1)Fe_(2)/C,Pt_(3)Fe_(4)/C,Pt_(1)Fe_(1)/C,and Pt_(2)Fe_(1)/C) are successfully prepared for enhanced anti-CO poisoning during methanol oxidation reaction(MOR).The optimal atomic ratio of Pt/Fe for the MOR is 1:2,and the mass activity of Pt_(1)Fe_(2)/C(5.40 A mg_(Pt)^(-1)) is 13.5 times higher than that of conventional commercial Pt/C(Pt/C-JM)(0.40 A mg_(Pt)^(-1)).The introduction of Fe into the Pt lattice forms the PtFe alloy phase,and the electron density of Pt is reduced after forming the PtFe alloy.In-situ Fourier transform infrared results indicate that the addition of oxyphilic metal Fe has reduced the adsorption of reactant molecules on Pt during the MOR.The doping of Fe atoms helps to desorb toxic intermediates and regenerate Pt active sites,promoting the cleavage of C-O bonds with good selectivity of CO_(2)(58.1%).Moreover,the Pt_(1)Fe_(2)/C catalyst exhibits higher CO tolerance,methanol electrooxidation activity,and long-term stability than other Pt_(x)Fe_(y)/C catalysts. | Qian Yang Sifan Zhang Fengshun Wu Lihua Zhu Guang Li Mingzhi Chen An Pei Yingliang Feng | 2024 | Journal of Energy Chemistry2024，90，3： | 0 |
| 6 | Effect of edge cracks on critical current degradation in REBCO tapes under tensile stress显示文摘The slitting process for manufacturing REBa2Cu3O7δ(REBCO,RE=Rare earth)tapes of required width significantly improves the production efficiency and reduces production costs.However,edge cracks induced by the slitting process of wide REBCO tapes may cause premature degradation under high tensile stress in highfield magnets.Therefore,it is necessary to evaluate the effect of edge cracks of REBCO tapes on the critical current(Ic)degradation.Firstly,Ic degradation under artificial cracks was measured to validate the applicability of linear elastic fracture mechanics for the REBCO layer.The maximum circumferential stress criterion was used to derive the mixed-mode stress intensity factor of multiple oblique edge cracks.A semi-analytical model considering edge crack properties such as angleβ,spacing d,and length a,was built to evaluate the critical load and critical crack.We found that when the stress intensity factor at the crack tip is below KIC?2:3 MPa ffiffiffiffim p,edge cracks did not propagate.We examined commercial REBCO tapes manufactured by two different processes,concluding that edge cracks in these tapes will not cause premature degradation. | Zhirong Yang Yi Li Peng Song Mingzhi Guan Feng Feng Timing Qu | 2022 | Superconductivity2022，，1： | 0 |
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