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A review of fundamental factors affecting diesel PM oxidation behaviors

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Science China(Technological Sciences) 2018年第3期61卷 330-345页

作者： GAO JianBing MA ChaoChen XING ShiKai SUN LiWei HUANG LiYong school of Mechanical Engineering Beijing Institute of Technology Department of Mechanical Engineering Sciences University of Surrey school of vocational and Technical Hebei Normal University

Diesel particulate matter(DPF) is usually employed to meet the stringent regulations on particulate matter(PM) emissions for diesel engine. To resolve the DPF regeneration problem, comprehensive information about the factors influencing PM oxidation behaviors must be understood. Large amounts of factors related to PM oxidation activity have been investigated, however, some relations are still ambiguous. This paper reviews the factors related to PM oxidation activity that the factors are divided into the engine-correlated and engine-uncorrelated factors. The methods with both advantages and disadvantages to test the oxidation behaviors are introduced. The microstructure and ingredient being fundamental factors affecting PM oxidation behaviors are as the principle line to correlate PM oxidation behaviors and engine-correlated factors. The relations of engine-correlated factors with oxidation behaviors are obtained though advanced technologies that are mutual complementation. The engine-uncorrelated factors are also reviewed that these factors are vital to oxidation activity changes. Multiple-factor analysis rather than single-factor analysis should be developed to make the oxidation behaviors of diesel PM more clear.

关键词： diesel PM oxidation behaviors microstructure ingredient

Construction 0D TiO_(2) nanoparticles/2D CoP nanosheets heterojunctions for enhanced photocatalytic H_(2) evolution activity

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Journal of Materials Science & Technology 2020年第21期56卷 196-205页

作者： Qinqin Liu Jinxin Huang Hua Tang Xiaohui Yu Jun Shen school of Materials Science and Engineering Jiangsu UniversityZhenjiang212013China school of Pharmacy Suzhou Vocational Health CollegeSuzhou215009China

It is still of gigantic challenging to design and to optimize photocatalytic systems with cost-efficiency for photocatalytic hydrogen evolution from water ***,noble-metal-free 2D CoP nanosheets were prepared by a phosphorization method using Co(OH)2 nanosheets as precursors,and then employed as photocatalytic cocatalyst and template to make 0D Ti O2 nanoparticles in-situ grow on the surface for construction of 0D/2D TiO_(2)/CoP hybrid by a simple hydrothermal *** TiO2/CoP hybrid with the optimal ratio of CoP cocatalyst(1 wt.%)manifested significantly improved photocatalytic H_(2) evolution rate of 0.604 mmol g^(-1) h^(-1),which is tenfold in comparison to pure TiO2(0.06 mmol g^(-1) h^(-1).The mechanism of performance enhancement was fully investigated and supposed that 2D CoP nanosheets cocatalyst can enhance the photo-absorption and provide more active sites for water reduction reaction;furthermore,2D CoP nanosheets with smaller work function and high conductivity would form an Ohmicjunction with TiO_(2) nanoparticles,which can significantly accelerate the separation of photo-generated charge carriers and improve the exploitation of the photoexcited electrons in water redox *** work is anticipated to impel more perspicacity into synthesizing innovative photocatalytic systems with 2D transition metal phosphides cocatalysts for attaining high photocatalytic H_(2) evolving pursuit.

关键词： Photocatalytic H_(2)evolution CoP nanosheets TiO_(2) 0D/2D heterojunction

Attractor comparison analysis for characterizing vertical upward oil gas water three-phase flow

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Chinese Physics B 2014年第3期23卷 361-368页

作者：赵俊英金宁德高忠科杜萌王振亚 school of Electrical Engineering and Automation Tianjin University Electronic Engineering Department Tianjin Vocational College of Electronics & Information

We investigate the dynamic characteristics of oil-gas-water three-phase flow in terms of chaotic attractor comparison. In particular, we extract a statistic to characterize the dynamical difference in attractor probability distribution. We first take time series from Logistic chaotic system with different parameters as examples to demonstrate the effectiveness of the method. Then we use this method to investigate the experimental signals from oil-gas-water three-phase flow. The results indicate that the extracted statistic is very sensitive to the change of flow parameters and can gain a quantitatively insight into the dynamic characteristics of different flow patterns.

关键词： oil-gas-water three-phase flow fluid dynamics attractor comparison

Predictive analysis for race detection in software-defined networks

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Science China(Information Sciences) 2019年第6期62卷 34-53页

作者： Gongzheng LU Lei XU Yibiao YANG Baowen XU State Key Laboratory of Novel Software Technology Nanjing University school of Computer Engineering Suzhou Vocational University

Race condition remains one kind of the most common concurrency bugs in software-defined networks(SDNs). The race conditions can be exploited to lead to security and reliability risks. However,the race conditions are notoriously difficult to detect. The existing race detectors for SDNs have limited detection capability. They can only detect the races in the original traces(observed traces) and cause false negatives. In this study, we present a predictive analysis framework called SDN-predict for race detection in SDNs. By encoding the order between the specified network events in SDNs as constraint, we formulate race detection as a constraint solving problem. In addition to detecting the races in the original trace, our framework can also detect the races in the feasible traces got from reordering the events in the original trace while satisfying the consistency requirements of trace. Moreover, we formally prove that our predictive analysis framework is sound and can achieve the maximal possible detection capability for any sound dynamic race detector with respect to the same trace. We evaluate our framework on a set of traces collected from three SDN controllers(POX, Floodlight, ONOS), running 5 representative applications including reactive and proactive applications in large networks, on three different network topologies. These experiments show that our framework has higher race detection capability than exisiting SDN race detector-SDNRacer, and detects more 1173 races. These 1173 races were previously undetected and confirmed by checking the race graphs.

关键词： constraint solving predictive analysis race detection software-defined networks

Effect of Flow Directions on Multiphase Flow Boiling Heat Transfer Enhanced by Suspending Particles in a Circulating Evaporation System

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Transactions of Tianjin University 2019年第3期25卷 201-213页

作者： Feng Jiang Teng Jiang Guopeng Qi Xiulun Li school of Chemical Engineering and Technology Tianjin University school of Biological and Environmental Engineering Tianjin Vocational Institute

A circulating fluidized bed evaporator(including down-flow, horizontal, and up-flow beds) was constructed to study the effect of flow directions on multiphase flow boiling heat transfer. A range of experimental investigations were carried out by varying amount of added particles(0-2%), circulation flow rate(2.15-5.16 m^3/h) and heat flux(8-16 kW/m^2). The comparison of heat transfer performance in different vertical heights of the horizontal bed was also discussed. Results reveal that the glass bead particle can enhance heat transfer compared with vapor-liquid two-phase flow for all beds. At a low heat flux(q = 8 kW/m), the heat-transfer-enhancing factor of the horizontal bed is obviously greater than those of the up-flow and down-flow beds. With the increase in the amount of added particles, the heat-transfer-enhancing factors of the up-flow and down-flow beds increase, whereas that of the horizontal bed initially increases and then decreases. However, at a high heat flux(q=16 kW/m), the heat-transfer-enhancing factors of the three beds show an increasing tendency with the increase in the amount of added particles and become closer than those at a low heat flux. For all beds, the heat-transfer-enhancing factor generally increases with the circulation flow rate but decreases with the increase in heat flux.

关键词： Heat transfer enhancement Circulating fluidized bed evaporator Flow direction Down-flow bed Up-flow bed Horizontal bed

Condensation of Self-Driven Particles in Scale-Free Networks

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Chinese Physics Letters 2010年第2期27卷 326-329页

作者：沈静 Department of Mechanical and Electrical Engineering Yancheng Mechanical and Electrical of Higher Vocational-Technical School Yancheng 224000

A new simple model of self-driven particles in scale-free networks is introduced to understand the emergence of condensation in the natural world. In the model, at each time step, particles are driven to choose their next habitats according to the particle numbers at both the present habitats and neighbors. It is found that the hub effect results in the condensation. The present numerical results as well as the theoretical analysis of condensation transition show the criterion of condensation. Both simulations and theoretical analysis display that there are three phases for different hopping probabilities δ： non-condensation （δ〈δc）, partial condensation （δc≤ δ〈1）, and complete condensation （δ≥δc＇= 1）, and the mean occupation particle number at the stationary state is also obtained. Moreover, the noise effect on self-driven particles is studied, and it makes particle numbers at nodes tend towards being identical.

关键词： Computational physics Statistical physics and nonlinear systems

Electrochemical and Theoretical Studies of 1-Alkyl-2-substituted Benzimidazoles as Corrosion Inhibitors for Carbon Steel Surface in HCl Medium

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Chinese Journal of Structural Chemistry 2016年第12期35卷 1829-1839页

作者：施红徐斌朱红军 school of Electrical and Mechanical Engineering Jiangsu Vocational College of Information Technology school of Chemistry and Molecular Engineering Nanjing Tech University

The inhibition efficiencies of newly synthesized four 1-alkyl-2-substituted benzimidazole compounds（a^d） have been studied for the corrosion of carbon steel in 1.0 M HCl by using potentiodynamic polarization measurement. The four inhibitors act as mixed-type inhibitors,which mainly inhibit cathodes. The inhibition efficiency of these compounds enhanced when the concentration of the inhibitors increased. A theoretical study of the corrosion inhibition efficiency of these compounds was carried out by using the B3 LYP level with the 6-31＋G＊ basis set. Considering the solvent effect,the IEFPCM model was selected. Furthermore,the adsorption energies of the inhibitors with the iron（001） surface were studied by using molecular dynamic（MD） simulations. The theoretical results show that these inhibitors all exhibit several adsorption active-centers. Meanwhile,the MD simulations indicate that the adsorption occurs mostly through benzene ring and the lone pair electrons of the nitro atoms. These results demonstrated that the theoretical studies and MD simulations are reliable and promising methods for analyzing the inhibition efficiency of organic inhibitors.

关键词： benzimidazole electrochemical techniques inhibitor DFT molecular dynamic

Heating rate effects for the melting transition of Pt-Ag-Au nanoalloys

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Chinese Physics B 2021年第10期30卷 638-644页

作者： Huseyin Yıldırım Ali Kemal Garip Yenice vocational school Karabuk UniversityKarabukTurkey Department of Physics Zonguldak Bulent Ecevit UniversityZonguldakTurkey

The classical molecular dynamics simulations in canonical NVT ensemble conditions are used to investigate the melting transition in different heating rates of Pt-Ag-Au ternary *** order to obtain the initial configurations used in the molecular dynamics simulations,optimizing the chemical ordering of Pt_(13)AgnAu_(42−n)(n=0-42)ternary nanoalloys was performed using the Basin-Hopping algorithm which would not allow changes in the icosahedron *** Gupta many-body potential was used to model interatomic interactions in both molecular dynamics simulations and optimization *** melting transitions of selected Pt-Ag-Au nanoalloys were explored using caloric curves and Lindemann *** have been two identified types of melting mechanisms,one includes sudden jump behavior in the caloric curve and the other is an isomerization while melting *** temperature range in which the isomerization takes place depends on the heating rate value.

关键词： chemical ordering melting optimization nanoalloys

Modified Projective Synchronization of Fractional-order Chaotic Systems with Different Dimensions

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Acta Mathematicae Applicatae Sinica 2020年第2期36卷 527-538页

作者： Xi ZHANG Ran-chao WU school of Mathematics Anhui UniversityHefei 230601China Nanchang No.1 Secondary vocational school Nanchang330013China

In this paper,the modified projective synchronization between two fractional-order chaotic systems with different dimensions is *** added-order scheme and the reduced-order scheme are proposed,*** on the Laplace transformation and feedback control theory,controllers are designed such that two chaotic systems with different dimensions could be synchronized asymptotically under the presented *** numerical simulations are given to show the effectiveness of the proposed schemes.

关键词： Modified projective synchronization Fractional-order chaotic systems Laplace transformation