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Salt-fog corrosion behavior of C/SiC and its effect on ablation resistance

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Journal of Materials Science & Technology 2019年第12期35卷 2772-2777页

作者： su Cheng xing Zhao gua.g Yang Yigua.g Wang Science and Technology on Thermostructural Composite Materials Laboratory Northwestern Polytechnical University

Carbon fiber-reinforced silicon carbide(C/SiC) composites are significantly important candidates for thermal protection materials. The corrosion mechanism of C/SiC composite materials is the basis of their optimization and application. In this study, structural evolution of C/SiC composites fabricated by chemical vapor infiltration was investigated in the salt-fog storage environment. Furthermore, the effect of salt-fog on their ablation behaviors under oxyacetylene flame environment was studied. The ablation morphologies and corrosion mechanisms of C/SiC composites were analyzed and discussed. The results indicated that silica layer with size of c.a. 20 nm was formed on the surface of composite. The extent of corrosion in salt fog was limited, and it had little effect on the ablation behavior of the C/SiC composites,as well on the tensile strength and bending strength.

关键词： Ceramic matrix composites Salt fog corrosion Oxidation Ablation property

Cadmium uptake and speciation changes in the rhizosphere of cadmium accumulator and non-accumulator oilseed rape varieties

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Journal of Environmental Sciences 2009年第8期21卷 1125-1128页

作者： su Dechun xing Jianping JIAO Weiping WONg Woonchung College of Resources and Environmental Sciences China Agricultural University Beijing 100193 China Department of Biology Hong Kong Baptist University Kowloon Tong Hong Kong SAR China

Characteristics of cadmium （Cd） uptake kinetics and distribution of Cd speciation in the rhizosphere for Cd accumulator and nonaccumulator oilseed rape varieties were investigated under nutrient solution and rhizobox soil culture conditions. The results showed that the maximal influx （Vmax） for Cd^2＋ and Km were significantly different for the two oilseed rape varieties. The value of Vmax for Cd accumulator oilseed rape Zhucang Huazi was two-fold greater than that for oilseed rape Chuan you Ⅱ-93. The exchangeable Cd concentration in the rhizosphere was significantly lower than in non-rhizospheric soils supplemented with CdSO4 for both the varieties. Carbonate-bound Cd in the rhizosphere of Cd accumulator oilseed rape was significantly higher than that in the rhizosphere of nonaccumulator oilseed rape and non-rhizospheric soil. Cd accumulator oilseed rape had a higher Cd^2＋ affinity and more ability to uptake insoluble Cd in the soil than the non-accumulator oilseed rape.

关键词： cadmium oilseed rape rhizosphere uptake kinetics

TWO INNOVATIVE COALITION FORMATION MODELS FOR DYNAMIC TASK ALLOCATION IN DISASTER RESCUES

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Journal of Systems Science and Systems Engineering 2018年第2期27卷 215-230页

作者： xing su YuechenWang Xibin Jia Limin guo Zhiming Ding Faculty of Information Beijing University of Technology Beijing 100124 China

This paper addresses the problem of multi-objective coalition formation for task allocation. In disaster rescue, due to the dynamics of environments, heterogeneity and complexity of tasks as well as limited available agents, it is hard for the single-objective and single （task）-to-single （agent） task allocation approaches to handle task allocation in such circumstances. To this end, two multi-objective coalition formation for task allocation models are proposed for disaster rescues in this paper. First, through coalition formation, the proposed models enable agents to cooperatively perform complex tasks that cannot be completed by single agent. In addition, through adjusting the weights of multiple task allocation objectives, the proposed models can employ the linear programming to generate more adaptive task allocation plans, which can satisfy different task allocation requirements in disaster rescue. Finally, through employing the multi-stage task allocation mechanism of the dynamic programming, the proposed models can handle the dynamics of tasks and agents in disaster environments. Experimental results indicate that the proposed models have good performance on coalition formation for task allocation in disaster environments, which can generate suitable task allocation plans according to various objectives of task allocation.

关键词： Disaster rescues multi-objective linear programming cooperative agents multi-stage taskallocation

A Light Weight Traffic Volume Prediction Approach Based on Finite Traffic Volume Data

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Journal of Systems Science and Systems Engineering 2023年第5期32卷 603-622页

作者： xing su Minghui Fan Zhi Cai Qing Liu Xiaojun Zhang Faculty of Information Technology Bering University of TechnologyBeijing100124China Shanghai Ocean University Shanghai201306China Academy of Opto-electronics Chinese Academy of SciencesBeijing100094China

As one of the key technologies of intelligent transportation systems, short-term traffic volume prediction plays an increasingly important role in solving urban traffic problems. In the last decade, many approaches were proposed for the traffic volume prediction from different perspectives. However, most of these approaches are based on a large amount of historical data. When there are only finite collected traffic data, they cannot be well trained, so the prediction accuracy of these approaches will be poor. In this paper, a tensor model is proposed to capture the change patterns of continuous traffic volumes. From collected traffic volume data, the element data are extracted to update the corresponding elements of the tensor model. Then, a tucker decomposition and gradient descent based algorithm is employed to impute the missing elements of the tensor model. After missing element imputation, the tensor model can be directly applied to the short-term traffic volume prediction through searching the corresponding elements of the model and the storage cost of the model is low. Our model is evaluated on real traffic volume data from PeMS dataset, which indicates that our model has higher traffic volume prediction accuracy than other approaches in the situation of finite traffic volume data.

关键词： Short-term traffic volume prediction tensor Tucker decomposition finite traffic volume data

Structure engineering of PtCu_(3)/C catalyst from disordered to ordered intermetallic compound with heat-treatment for the methanol electrooxidation reaction

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Nano Research 2022年第5期15卷 3866-3871页

作者： Zihao xing Jun Li Shun Wang Chenliang su Huile Jin Institute of New Materials&Industry Technology Wenzhou UniversityWenzhou 325024China Institute of Microscale Optoelectronics Shenzhen UniversityShenzhen 518060China

Platinum based alloys are hereinto the mostly used methanol oxidation ***,there are limited ways to improve the methanol oxidation reaction(MOR)performance of catalysts in terms of both activity and *** we developed a simple heat-treatment method to synthesize PtCu_(3)/C intermetallic compound catalyst with lattice *** as-prepared PtCu_(3)/C-1000 exhibited high specific activity of 3.23 mA·cm^(-1) and mass activity of 1,200 mA·mgPt^(-1),which is much higher than the PtCu_(3)/C-untreated and commercial Pt/C catalysts,*** XAS and DFT results shows the high activity of the catalyst towards MOR comes from the tightening of the Pt-M bond,which leads to the decrease of Fermi energy level and the make it difficulty in adsorbing carbon intermediates,thus releasing more active sites to promote the improvement of MOR ***,the PtCu_(3)/C-1000 shows better stability which is due to the surface-rich Pt prevents Cu from dissolution.

关键词： methanol electrooxidation PtCu_(3)alloy catalyst lattice compression composition reconstruction heat-treatment

Bayesian inference for ammunition demand based on gompertz distribution

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Journal of Systems Engineering and Electronics 2020年第3期31卷 567-577页

作者： ZHAO Rudong SHI Xianming WANg Qian su Xiaobo SONg xing Department of Equipment Command and Management Shijiazhuang CampusArmy Engineering UniversityShijiazhuang 050003China Unit 73127 of the PLA Fuzhou 350503China The Ninth Comprehensive Training Base of Army Zhangjiakou 075000China Army Infantry College of the PLA Shijiazhuang 050003China Unit 68303 of the PLA Golmud 816000China

Aiming at the problem that the consumption data of new ammunition is less and the demand is difficult to predict,combined with the law of ammunition consumption under different damage grades,a Bayesian inference method for ammunition demand based on gompertz distribution is *** Bayesian inference model based on gompertz distribution is constructed,and the system contribution degree is introduced to determine the weight of the multi-source *** the case where the prior distribution is known and the distribution of the field data is unknown,the consistency test is performed on the prior information,and the consistency test problem is transformed into the goodness of the fit test *** the Bayesian inference is solved by the Markov chain-Monte Carlo(MCMC)method,and the ammunition demand under different damage grades is *** example verifies the accuracy of this method and solves the problem of ammunition demand prediction in the case of insufficient samples.

关键词： ammunition demand prediction Bayesian inference gompertz distribution system contribution Markov chain-Monte Carlo(MCMC)method

Preparation and characterization of core-shell Al@PFHP with improving the combustion and ignition properties of aluminum powder

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Particuology 2023年第6期77卷 62-70页

作者： Lichen Zhang Shuo Wang xing su Xiaodong Li Meishuai Zou School of Materials Science and Engineering Beijing Institute of TechnologyBeijing100081China

The dense alumina shell on the surface of aluminum powder will hinder the combustion of aluminum powder and increase its ignition *** this study,the aluminum oxide shell layer on the surface of aluminum powder was removed with hydrofluoric acid by one-pot method,and 3-Perfluorohexyl-1,2-epoxypropane(PFHP)(F3C(CF2)5CH2C2H3O)was coated to form a uniform and controllable core-shell Al@*** core-shell AI@PFHP showed better thermal reaction and ignition *** exothermic enthalpy of Al@0.15 PFHP was increased by about 1.9 times,with lower ignition temperature(reduced by about 140℃)and longer burning duration(increased by about 1.5 times)after coating with PFHP,compared with raw aluminum *** addition,the formation of PFHP coating shell can effectively improve the hydrophobicity and corrosion resistance of aluminum powder.

关键词： Aluminumpowder Core-shell 3-Perfluorohexyl-1 2-Epoxypropane Combustion

A 3D MIL-101@rgO composite as catalyst for efficient conversion of straw cellulose into valuable organic acid

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Chinese Chemical Letters 2022年第5期33卷 2573-2578页

作者： Yuan su Mengchu Lu Ruidian su Weizhi Zhou xing Xu Qian Li School of Mathematic and Quantitative Economics Shandong University of Finance and EconomicsJi’nan 250014China Shandong Key Laboratory of Water Pollution Control and Resource Reuse School of Environmental Science and EngineeringShandong UniversityQingdao 266200China School of Civil Engineering Shandong UniversityJi’nan 250100China

Efficient conversion of straw cellulose to chemicals or fuels is an attracting topic today for the utiliza-tion of biomass to substitute for fossil *** development of catalysts is of vital *** this work,a composite catalyst metal-organic frameworks(MOFs)immobilized on three-dimensional reduced graphene oxide(3D-rgO)were synthesized by in situ growth of the MIL-101(Cr)within the 3D-rgO *** supporting of 3D-rgO guaranteed the dispersion and acid site density of MIL-101(Cr).The MIL-101(Cr)@3D-rgO nanocomposite possesses excellent catalytic activity,stability,recyclability and is an idea catalyst for the efficient degradation of straw cellulose into formic acid(FA),acetic acid(AA)and oxalic acid(OA).A maximum FA conversion rates of 95.36%was obtained by using MIL-101(Cr)@3D-rgO(1:1)as catalyst and hydrothermal reaction at mild conditions of 200°C for 1h in alkaline aqueous *** MIL-101(Cr)@3D-rgO nanocomposite can be reused with high catalytic activity without any collapse of structure or leaching of chromium.

关键词： Straw cellulose MIL-101(Cr) Three-dimensional graphene Catalystic conversion Organic acid

An Innovative Approach for the Short-term Traffic Flow Prediction

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Journal of Systems Science and Systems Engineering 2021年第5期30卷 519-532页

作者： xing su Minghui Fan Minjie Zhang Yi Liang Limin guo Faculty of Information Technology Beijing University of TechnologyBeijing 100124China Faculty of Engineering and Information Sciences University of WollongongNSW 2500Australia

Traffic flow prediction plays an important role in intelligent transportation applications,such as traffic control,navigation,path planning,etc.,which are closely related to people's daily *** the last twenty years,many traffic flow prediction approaches have been ***,some of these approaches use the regression based mechanisms,which cannot achieve accurate short-term traffic flow ***,other approaches use the neural network based mechanisms,which cannot work well with limited amount of training *** this end,a light weight tensor-based traffic flow prediction approach is proposed,which can achieve efficient and accurate short-term traffic flow prediction with continuous traffic flow data in a limited period of *** the proposed approach,first,a tensor-based traffic flow model is proposed to establish the multi-dimensional relationships for traffic flow values in continuous time ***,a CANDECOMP/PARAFAC decomposition based algorithm is employed to complete the missing values in the constructed ***,the completed tensor can be directly used to achieve efficient and accurate traffic flow *** experiments on the real dataset indicate that the proposed approach outperforms many current approaches on traffic flow prediction with limited amount of traffic flow data.

关键词： Short-term traffic flow prediction tensor CP decomposition limited amount of data