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Ni-P-Nanodiamond composite electroless plating

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Acta Metallurgica Sinica(English Letters) 2010年第6期23卷 409-415页

作者： Yongwei ZHU yongjun chen Changhong ZHU Xiangqian SHEN College of Mechanical and Electrical Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016 China School of Materials Science and Technology Jiangsu Uaiversity Zhenjiang 212013 China

The effect of nanodiamond content in electrolyte and rotational speed of the stirrer on the deposition rate of coatings, the nanodiamond content in coatings, the micro- structure and the micro-hardness of coatings were studicd. A self-made pin-on-disk tribo-meter was employed to evaluate the wear resistance of prepared coatings. Re- sults show that the thickness of composite coating decreases with the rotational speed, while the micro hardness of coating and the content of nanodiamond in coating increase with increasing its content in electrolyte. The wear resistance of the composite coating deposited in an electrolye with 6 g/L nanodiamond increases by 50% in contrast with the pure Ni-P coating.

关键词： Nanodiamond Composite electroless plating Micro-hardness Wear resistance

An improved model for predicting hydrate phase equilibrium in marine sediment environment

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Journal of Natural Gas Chemistry 2010年第3期19卷 241-245页

作者： Yongchen Song Mingjun Yang yongjun chen Qingping Li Key Laboratory of Ocean Energy Utilization and Energy Conservation of Ministry of Education Dalian University of Technology Dalian 116024 Liaoning China CNOOC Research Center Beijing 100027 China

Based on the models of hydrate phase equilibrium in bulk water and porous media,an improved model was proposed to predict the methane hydrate equilibrium in marine sediment *** the suggested model,mechanical equilibrium of force between the interfaces in hydrate-liquid-vapor system was *** electrolyte was present in pore water,interfacial energy between hydrate and liquid was corrected by an equation that is expressed as the function of temperature and electrolyte *** activity of water is calculated based on the Pitzer model and the interfacial energy between liquid and gas is solved using the Li *** prediction results show good agreement with the experimental *** comparison with other models,it is proved that this model can improve the accuracy for predicting hydrate phase equilibrium in marine sediment environment.

关键词： hydrate equilibrium interfacial energy marine sediment

Reliable optimization of corridor capacity for China high speed railway by considering passenger service

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International Journal of Modeling, Simulation, and Scientific Computing 2017年第4期8卷 122-139页

作者： Mo Gao Leishan Zhou yongjun chen School of Traffic and Transportation Beijing Jiaotong University Beijing 100044P.R.China School of Economics and Management Engineering Beijing University of Civil Engineering and ArchitectureBeijing 100044P.R.China

Railway capacity has been extensively investigated for the purpose of utilizing rail infrastructure in a possible efficient ***,the estimation of high speed rail(HSR),which is different from common railways in many aspects,is still a challenge work needed to be ***,this work focuses on the capacity estimation of HSR *** objectives and constraints are developed for the HSR with the consideration of passenger service level and buffer time uncertainty,and a two-stage optimization model is *** first stage determines the optimal number of trains in terms of the passenger origin–destination demand,and the second stage is a multi-objective mixed integer programming(MO-MIP)aiming to estimate the optimal capacity *** branch-and-bound algorithm is extended and applied to the proposed model,and a case study is performed to Beijing–Shanghai HSR *** optimal solution is obtained,and the sensitivity of the two objectives is analyzed.

关键词： Railway capacity China high speed rail multi-objective mixed integer programming

The detection of tetrahydrofuran hydrate formation and saturation using magnetic resonance imaging technique

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Journal of Natural Gas Chemistry 2010年第3期19卷 224-228页

作者： Yu Liu Yongchen Song yongjun chen Lei Yao Qingping Li Key Lab of Ocean Energy Utilization and Energy Conservation of Ministry of Education Dalian University of Technology Dalian 116024 Liaoning China Research Center of China National Offshore Oil Corporation Beijing 100027 China

Tetrahydrofuran（THF） hydrate was formed in bulk as well as in glass beads pack with a mean diameter of 3.0 mm by controlling the temperature under ambient *** of THF hydrate formation procedure were obtained using the magnetic resonance imaging（MRI） *** experiment results showed that MRI is an effective method for the detection of hydrate *** of hydrate formed both in bulk and glass beads can be confirmed by intensity integration of MRI images.

关键词： tetrahydrofuran hydrate magnetic resonance imaging glass beads saturation

Investigation on the Effect of the Multilayered Porous Structure of Sea Urchin Skeleton on Its Mechanical Behavior

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Journal of Bionic Engineering 2020年第3期17卷 469-483页

作者： Hui Yu Jianbao Li Zhenhao Hou Jianlin Li yongjun chen Chunfu Lin School of Materials and Chemical Engineering Pingxiang UniversityPingxiang 337055China State Key Laboratory of Marine Resource Utilization in South China Sea College of Materials&Chemical EngineeringHainan UniversityHaikou 570228China

In this paper,the effect of stereom structure on the mechanical behavior of the Sea Urchin Inorganic Skeleton(SUIS)has been *** stereom microstructure of both Anthocidaris crassispina and Tripnenstes gratilla was characterized by Scanning Electron Microscopy(SEM).Results indicate that a three-layer porous structure consisting of a growth,a support,and a resorption(GSR)layer is a common denominator for both *** effect of GSR layer order on the mechanical behavior of the SUIS was studied by a finite element *** results show that the GSR model could effectively reduce the maximum tensile stress on its meridional sutures under unidirectional pressure,hydrostatic pressure,and self-weight *** a fabricated three-layered ceramic test strips with different layer orders,the mechanical properties have a completely opposite performance compared with the compressive properties of the calculated SUIS-Iike *** indicates that the GSR structure can effectively improve the mechanical properties of the SUIS,but it cannot be applied to bionics without considering its synergistic effect with the macro-structure of the *** is a typical example of bionic invalidation by single structure,where multi-level structure bionics may be an effective solution.

关键词： porous multilayered structure finite element analysis stress transfer mechanical properties sea urchin test

In Situ Investigation of Dynamic Silver Crystallization Driven by Chemical Reaction and Diffusion

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Research 2020年第1期2020卷 739-749页

作者： Ting Liu Xiangyu Dou Yonghui Xu yongjun chen Yongsheng Han State Key Laboratory of Multiphase Complex Systems Institute of Process EngineeringChinese Academy of Sciences100190 BeijingChina State Key Laboratory of Marine Resource Utilization in South China Sea Hainan University570228 HaikouChina School of Chemical Engineering University of Chinese Academy of Sciences100049 BeijingChina

Rational synthesis of materials is a long-term challenging issue due to the poor understanding on the formation mechanism of material structure and the limited capability in controlling nanoscale *** emergent in situ electron microscope provides an insight to this *** employing an in situ scanning electron microscope,silver crystallization is investigated in real time,in which a reversible crystallization is *** disclose this reversible crystallization,the radicals generated by the irradiation of electron beam are *** is found that the concentrations of radicals are spatiotemporally variable in the liquid cell due to the diffusion and reaction of *** fluctuation of the reductive hydrated electrons and the oxidative hydroxyl radicals in the cell leads to the alternative dominance of the reduction and oxidation *** reduction leads to the growth of silver crystals while the oxidation leads to their dissolution,which results in the reversible silver crystallization.A regulation of radical distribution by electron dose rates leads to the formation of diverse silver structures,confirming the dominant role of local chemical concentration in the structure evolution of materials.

关键词： silver reversible crystallization

Strengthening the Mechanical Performance of Sea Urchin Skeleton by Tube Feet Pore

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Journal of Bionic Engineering 2019年第1期16卷 66-75页

作者： Hui Yu Tianye Lin Yu Xin Jianlin Li Jianbao Li yongjun chen Xianzhi chen Longyang Liu State Key Laboratory of Marine Resource Utilization in South China Sea College of Materials &Chemical Engineering Hainan UniversityHaikou 570228China

In this paper,the effects of tube feet pores on the mechanical properties of Sea Urchin Skeleton (SUS) have been *** pore structure of drop-like Tripnenstes gratilla (a sea urchin) skeleton is characterized by Scanning Electron Microscopy (SEM).Based upon the data,the finite element method has been employed to analyze the Maximum Tensile Stress (MTS) of SUS models with different pore positions,accompanied by compressive tests on SUS-like *** indicate that for a drop-like SUS,the MTS keeps a linear relationship with the maximum load applied on the *** importantly,the mechanical performances of some perforated SUSs are better than their non-perforated counterparts due to their lower MTS values,*** maximum load can thus be increased by 35% when the pore is perforated at-10°.The strengthening is attributed to the introduced pore that causes the redistribution of stress and partly reduces the stress intensity on the original MTS *** contrast,the pore only increases the MTS value of a spherical shell under isostatic pressure or unidirectional *** is a strong hint that the drop-like shape of SUS has evolved to work with the tube feet pores to better protect their bodies.

关键词： tube feet pore sea urchin skeleton strengthening mechanism mechanical performances finite element method

Catalyst-free tandem Michael addition-cyclization reactions in aqueous media for the synthesis of benzimidazo[1,2-a]pyrimidinone derivatives

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Science China Chemistry 2010年第7期53卷 1492-1496页

作者： REN ChuanLi WANG Yan WANG Dong chen yongjun LIU Li Beijing National Laboratory(BNLMS) CAS Key Laboratory for Molecular Recognition and FunctionInstitute of ChemistryChinese Academy of SciencesBeijing 100190China

The catalyst-free reactions of Baylis-Hillman alcohols (1a-i) with 2-aminobenzimidazole (2) in THF-H2O (1:4) were developed for the convenient and greener synthesis of benzimidazo[1,2-a]pyrimidinone derivatives (3a-i).The pesticidal activities of 3a-i were examined to investigate a new biological activity of the imidazo[1,2-a]pyrimidinone-type compounds.

关键词： aqueous media Baylis-Hillman alcohol 2-aminobenzimidazole pesticidal activity

Mo_(3)Nb_(14)O_(44): A New Li^(+) Container for High-Performance Electrochemical Energy Storage

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Energy & Environmental Materials 2021年第1期4卷 65-71页

作者： Renjie Li Guisheng Liang Xiangzhen Zhu Qingfeng Fu yongjun chen Lijie Luo Chunfu Lin Institute of Materials for Energy and Environment School of Materials Science and EngineeringQingdao UniversityQingdao 266071China School of Materials Science and Engineering Hainan UniversityHaikou 570228China Songshan Lake Materials Laboratory Dongguan 523808China

Intercalating Nb-based oxides are promising anode compounds for lithiumion batteries since they have both good safety and large ***,the research in this field is still ***,Mo_(3)Nb_(14)O_(44)with a large theoretical capacity of 398 mAh g^(–1)(Mo^(64)←→Mo^(4+)and Nb^(5+)←→Nb^(3+))is exploited as a new Nb-based oxide anode compound,and Mo_(3)Nb_(14)O_(44)micron-sized particles(Mo_(3)Nb_(14)O_(44)-M)and Mo3Nb14O44 nanowires(Mo_(3)Nb_(14)O_(44)-N)are ***3Nb14O44 owns a tetragonal shear ReO_(3)crystal structure(high-symmetric 14 space group)constructed by 4×4×∞(Mo,Nb)O_(6)octahedron blocks linked by Mo O4 tetrahedra,forming an A–B–A layered structure with a large interlayer *** interesting structure allows fast Li+storage within the interlayers and significant intercalation-pseudocapacitive behavior,leading to the high rate performance of Mo_(3)Nb_(14)O_(44)-M/Mo_(3)Nb_(14)O_(44)-N with a large 10 C versus 0.1 C capacity retention percentage of 38.1/54.2%.Mo_(3)Nb_(14)O_(44)-M/Mo_(3)Nb_(14)O_(44)-N further exhibits a safe operating potential of 1.72/1.68 V,large reversible capacity of 323/321 m Ah g^(–1)at 0.1 C,high initial coulombic efficiency of 92.2/90.0%,and good cycling stability with 71.8/75.8%capacity retention after 1000 cycles at10 ***,a Li Mn_(2)O_(4)/Mo_(3)Nb_(14)O_(44)-N full cell also performs ***,Mo_(3)Nb_(14)O_(44)holds great promise as a fast-charging,safe,largecapacity,high-efficient,and long-life Li^(+)anode container.

关键词： anode in situ XRD Li^(+)storage Mo3Nb14O44 shear ReO3 crystal structure