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Effects of Area Discontinuity at Nozzle Inlet on the Characteristics of Self-resonating Cavitating Waterjet

Chinese Journal of Mechanical Engineering 2016年第4期29卷 813-824页

作者： LI deng KANG yong DING Xiaolong WANG Xiaochuan FANG Zhenlong School of Power and Mechanical Engineering Wuhan University Hubei Key Laboratory of Waterjet Theory and New Technology Wuhan University Department of Mechanical Science and Engineering University of Illinois at Urbana-Champaign

The current research on self-resonating cavitating waterjet（SRCW） mainly focuses on the generation mechanism and structure *** relating to the influences of disturbances at nozzle inlet on the characteristics of the jet are rarely *** order to further improve the performance of SRCW,effects of area discontinuity（enlargement and contraction） are experimentally investigated using three organ-pipe *** pressure oscillation peak and amplitude as well as aggressive erosion intensity of the jet are used to evaluate the *** results reveal that area enlargement and contraction affect the peak differently,depending on the inlet pressure,nozzle geometry,and standoff distance;while area contraction always improves the amplitude regardless of these *** inlet pressures of 10 MPa and 20 MPa,area discontinuity improves the peak at almost all the testing standoff distances,while this only happens at smaller standoff distances with the inlet pressure increased to 30 *** capability of area discontinuity for improving the amplitude is enhancing with increasing inlet ***,the cavitation erosion ability of the jet can be largely enhanced around the optimum standoff distance,depending on the type of area discontinuity and nozzle geometry.A preliminary analysis of the influence of area discontinuity on the disturbance waves in the flow is also *** proposed research provides a new method for effectively enhancing the performance of SRCW.

关键词： area discontinuity self-resonating cavitating waterjet(SRCW) organ-pipe nozzle pressure oscillation cavitation erosion

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Preparation and Characterization of KNO3/Diatomite Shape-Stabilized Composite Phase Change Material for High Temperature Thermal Energy Storage

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Journal of Materials Science & Technology 2017年第2期33卷 198-203页

作者： yong deng Jinhong Li Tingting Qian Weimin Guan Xiang Wang Beijing Key Laboratory of Materials Utilization of Nonmetallic Minerals and Solid Wastes National Laboratory of Mineral Materials School of Materials Science and Technology China University of Geosciences Beijing 100083 China

A new potassium nitrate （KNO3）]diatomite shape-stabilized composite phase change material （SS- CPCM） was prepared by the mixing and sintering method. KNO3 served as the phase change material （PCM） for thermal energy storage, while diatomite acted as the carrier matrix to provide the structural strength and prevent the leakage of PCM. It was found that KNO3 could be retained 65 wt% into pores and on surfaces of diatomite without the leakage of melted KNO3 from the SS-CPCM. The calculated filling rate of molten KNO3 that could enter into the disc-like shape pore of diatomite verified the scanning elec- tronic microscopy images of SS-CPCM. X-ray diffraction and Fourier transform infrared spectroscopy results showed that no reaction occurred between KNO3 and diatomite, performing good compatibility. Accord- ing to the differential scanning calorimetry results, after 50 thermal cycles, the phase change temperatures for melting and freezing of SS-CPCM with 65 wt% KNO3 were changed from 330.23 ℃ and 332.90 ℃ to 330.11 ℃ and 332.84 ℃ and corresponding latent heats varied from 60.52 J/g and 47.30 J/g to 54.64 J/g and 41.25 J/g, respectively. The KNO3/diatomite SS-CPCM may be considered as a potential storage media in solar power plants for thermal energy storage.

关键词： Potassium nitrate Diatomite Shape-stabilized composite phase change material Thermal energy storage

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Organic-acid-assisted synthesis of a 3D lasagna-like Fe-N-doped CNTs-G framework： An efficient and stable electrocatalyst for oxygen reduction reactions

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Nano Research 2017年第4期10卷 1258-1267页

作者： Xiaobing Bao Yutong Gong Jiang deng Shiping Wang yong Wang Advanced Materials and Catalysis Group ZJU-NHU United R&D Center Center for Chemistry of High-Performance and Novel Materials Department of Chemistry Zhejiang University Hangzhou 310028 China

The scalable preparation of multi-functional three-dimensional （3D） carbon nanotubes and graphene （CNTs-G） hybrids via a well-controlled route is urgently required and challenging. Herein, an easily operated, oxalic acid-assisted method was developed for the in situ fabrication of a 3D lasagna-like Fe-N-doped CNTs-G framework （LMFC） from a precursor designed at the molecular level. The well-organized architecture of LMFC was constructed by multi-dimensionally interconnected graphene and CNTs which derived from porous graphene sheets, to form a fundamentally robust and hierarchical porous structure, as well as favorable conductive networks. The impressive oxygen reduction reaction （ORR） performances in both alkaline and acidic conditions helped confirm the significance of this technically favorable morphological structure. This product was also the subject of research for the exploration of decisive effects on the performance of ORR catalysts with reasonable control variables. The present work further advances the construction of novel 3D carbon architectures via practical and economic routes.

关键词： well-controlled oxalic acid robust three-dimensional (3D) lasagna-like framework impressive oxygen reduction reaction (ORR) performances

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Fine-grained P2P traffic classification by simply counting flows

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Frontiers of Information Technology & Electronic Engineering 2015年第5期16卷 391-403页

作者： Jie HE Yue-xiang YANG yong QIAO Wen-ping deng College of Computer National University of Defense Technology The Research Institution China Electronic Equipment & System Engineering Company

The continuous emerging of peer-to-peer(P2P) applications enriches resource sharing by networks, but it also brings about many challenges to network management. Therefore, P2 P applications monitoring, in particular,P2 P traffic classification, is becoming increasingly important. In this paper, we propose a novel approach for accurate P2 P traffic classification at a fine-grained level. Our approach relies only on counting some special flows that are appearing frequently and steadily in the traffic generated by specific P2 P applications. In contrast to existing methods, the main contribution of our approach can be summarized as the following two aspects. Firstly, it can achieve a high classification accuracy by exploiting only several generic properties of flows rather than complicated features and sophisticated techniques. Secondly, it can work well even if the classification target is running with other high bandwidth-consuming applications, outperforming most existing host-based approaches, which are incapable of dealing with this situation. We evaluated the performance of our approach on a real-world trace. Experimental results show that P2 P applications can be classified with a true positive rate higher than 97.22% and a false positive rate lower than 2.78%.

关键词： Traffic classification Peer-to-peer(P2P) Fine-grained Host-based

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Improved analysis of the rare decay processes of Λ_(b)

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Communications in Theoretical Physics 2021年第10期73卷 114-124页

作者： Ren-hao deng yong-lu Liu Ming-qiu Huang College of Art and Science National University of Defense TechnologyHunan 410073China

It is noted that in the new Particle Data Group(PDG) version the rare decays of the Λ_(b) baryon have been revised with more accuracy. The new results show that most of the existing theoretical results on the process Λ_(b)→Λ_(γ) Lgbare larger than those of experiments. With the improved higher-order light-cone distribution amplitudes of the Λ baryon, we reanalyze the process in the framework of light-cone quantum chromodynamics sum rules and the branching ratio is estimated to be Br (Λ_(b)→Λ_(γ))=(7.38-0.39+0.40)×10^(16), which is consistent with the new experimental result. Furthermore, another process Λ_(b)→Λl+l- is also analyzed in the same frame. The final branching ratio is calculated to be Br (Λ_(b)→Λl+l-)=1.20×10^(-6), which is in good accordance with the data from the PDG and other theoretical predictions.

关键词： light-cone distribution amplitude rare decay light-cone QCD sum rules

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New conflict representation model in generalized power space

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Journal of Systems Engineering and Electronics 2012年第1期23卷 1-9页

作者： You He Lifang Hu Xin Guan Deqiang Han yong deng Research Institute of Information Fusion Naval Aeronautical and Astronautical University Yantai 264001 E R. China Navy Armament Academy Beijing 102249 P. R. China College of Electronic Science and Engineering National University of Defense Technology Changsha 410073 E R. China Institute of Integrated Automation Xi＇an Jiaotong University Xi＇an 710049 E R. China School of Electronics and Information Technology Shanghai Jiaotong University Shanghai 200240 E R. China

The study on alternative combination rules in Dempster- Shafer theory （DST） when evidences are in conflict has emerged again recently as an interesting topic, especially in data/information fusion applications. The earlier researches have mainly focused on investigating the alternative which would be appropriate for the conflicting situation, under the assumption that a conflict is identified. However, the current research shows that not only the combination rule but also the classical conflict coefficient in DST are not correct to determine the conflict degree between two pieces of evidences. Most existing methods of measuring conflict do not consider the open world situation, whose frame of discernment is incomplete. To solve this problem, a new conflict representa- tion model to determine the conflict degree between evidences is proposed in the generalized power space, which contains two parameters： the conflict distance and the conflict coefficient of inconsistent evidences. This paper argues that only when the con- flict measure value in the new representation model is high, it is safe to say the evidences are in conflict. Experiments illustrate the efficiency of the proposed conflict representation model.

关键词： Dezert-Smarandache theory (DSmT) conflict evidence Dempster rule of combination information fusion.

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Investigating the flow characteristics of air-lift pumps operating in gas-liquid two-phase flow

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Chinese Journal of Chemical Engineering 2018年第2期26卷 219-227页

作者： Zhineng Wang yong Kang Xiaochuan Wang deng Li Dong Hu Key Laboratory of Hydraulic Machinery Transients Ministry of Education Wuhan University Wuhan 430072 China Hubei Key Laboratory of Waterjet Theory and New Technology Wuhan University Wuhan 430072 China School of Power and Mechanical Engineering Wuhan University Wuhan 430072 China

Experiments were conducted to investigate the flow characteristics in the riser pipe and the suction pipe of airlift pump at a series of air flow rates and submergence ratios by using a high speed camcorder and a Laser Doppler Velocimetvy system （LDV）. A modified model was developed to predict the performance of airlift pump operating in gas-liquid two-phase flow, The results show that an unstable flow structure composed by a water falling film, a bubbly mixture, a water ascending film appearing alternately in riser pipe dominates the performance of airlift pump at large air flow rates. The bubbly mixture with a strongest capacity for pumping water first increases to its maximum and then slightly decreases. In suction pipe, the average velocity shows a flat profile and increases with increasing submergence ratio. Moreover, the predicted results of modified model are in good agreement with the experimental data in a margin of ± 12%.

关键词： PumpGas-liquid flowMixturesFlow structureRiser pipe

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Measuring Conflict Functions in Generalized Power Space

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Chinese Journal of Aeronautics 2011年第1期24卷 65-73页

作者： HU Lifang GUAN Xin deng yong HAN Deqiang HE You Research Institute of Information Fusion Naval Aeronautical and Astronautical University Yantai 264001 China Sche Institute of Electronic Science and Engineering National University of Defense Technology Changsha 410073 China School of Electronics and Information Technology Shanghai Jiaotong University Shanghai 200240 China Institute of Integrated Automation Xi 'an Jiaotong University Xi 'an 710049 China

One of the most important open issues is that the classical conflict coefficient in D-S evidence theory （DST） cannot correctly determine the conflict degree between two pieces of evidence. This drawback greatly limits the use of DST in real application systems. Early researches mainly focused on the improvement of Dempster’s rule of combination （DRC）. However, the current research shows it is very important to define new conflict coefficients to determine the conflict degree between two or more pieces of evidence. The evidential sources of information are considered in this work and the definition of a conflict measure function （CMF） is proposed for selecting some useful CMFs in the next fusion work when sources are available at each instant. Firstly, the definition and theorems of CMF are put forward. Secondly, some typical CMFs are extended and then new CMFs are put forward. Finally, experiments illustrate that the CMF based on Jousselme and its similar ones are the best suited ones.

关键词： D-S evidence theory conflict evidence generalized power space information fusion uncertainty

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Effect of low-speed waterjet pressure on the rock-breaking performance of unsubmerged cavitating abrasive waterjet

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Petroleum Science 2024年第4期21卷 2638-2649页

作者： Chen-Xing Fan deng Li yong Kang Hai-Tao Zhang Hubei Key Laboratory of Waterjet Theory and New Technology Wuhan UniversityWuhan430072HubeiChina School of Power and Mechanical Engineering Wuhan UniversityWuhan430072HubeiChina

Unsubmerged cavitating abrasive waterjet(UCAWJ)has been shown to artificially create a submerged environment that produces shear cavitation,which effectively enhances rock-breaking *** shear cavitation generation and collapse intensity depend on the pressure difference between the intermediate high-speed abrasive waterjet and the coaxial low-speed ***,the effect of the pressure of the coaxial low-speed waterjet is *** this purpose,the effect of low-speed waterjet pressure on rock-breaking performance at different standoff distances was experimentally investigated,and the effects of erosion time and ruby nozzle diameter on erosion performance were ***,the micromorphology of the sandstone was observed at different *** results show that increased erosion time and ruby nozzle diameter can significantly improve the rock-breaking *** different standoff distances,the mass loss increases first and then decreases with the increase of low-speed waterjet pressure,the maximum mass loss is 10.4 g at a low-speed waterjet pressure of0.09 *** surface morphology of cavitation erosion was measured using a 3D profiler,the increase in both erosion depth and surface roughness indicated a significant increase in the intensity of the shear cavitation *** a low-speed waterjet pressure of 0.18 MPa,the cavitation erosion surface depth can reach 600μm with a roughness of 127μm.

关键词： Rock-breaking Coaxial low-speed waterjet pressure Abrasive waterjet Cavitation Unsubmerged environment

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Effect of Basicity on Deoxidation Capability of Refining Slag

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Journal of Iron and Steel Research International 2013年第2期20卷 21-26页

作者： deng Zhi-yin ZHU Miao-yong ZHONG Bao-jun DAI yong-gang School of Materials and Metallurgy Northeastern University Technology Center Xingtai Iron and Steel Co Ltd

Mass action concentration （activity） calculation model was used to analyze the variation rule of mass action concentrations of slag compositions with basicity changing, and the effect of basicity on deoxidation capability and control of spinel and globular inclusions was investigated theoretically. From the calculation and experimental results, it was found that with the increase of basicity, the mass action concentration of Al2O3 and SiO2 decreases, while the mass action concentration of FeO and MgO increases at first and then *** basicity below 3 to 4 would help to control spinel inclusions formation, and higher basicity improves formation of globular inclusions. Slag with basicity under 2 can effectively control the formation of globular inclusions. Deoxidation capability of slag increases with the increase of basicity, and slag with basicity about 4 could almost reach the maximum deoxidation capability. In order to smelt low oxygen steel with globular inclusions controlled, refining slag basicity should be controlled at about 4.

关键词： deoxidation mass action concentration activity basicity inclusion

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