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Temperature Characteristics of Cathode Sheath in High-Pressure Volume Discharge Derived from Emanating Shock Wave

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Chinese Physics Letters 2012年第12期29卷 137-140页

作者： YANG Chen-guang XU Yong-Yue zuo Du-luo Wuhan National Laboratory for Optoelectronics Huazhong University of Science and TechnologyWuhan 430074 Institute of Optoelectronic Science and Engineering Huazhong University of Science and TechnologyWuhan 430074

The temperature characteristics of cathode sheath in high-pressure volume discharge are investigated *** cathode sheath temperatures under various discharge conditions are derived from the speeds of the emanating shock waves which are measured by a Mach-Zehnder *** is found that the cathode sheath temperature and the ratioΔT_(3)/ΔT_(1) of temperature rise between cathode sheath and plasma bulk are determined by the specific energy deposition and the breakdown delay time *** results are helpful for discharge stability improving and shock wave reducing.

关键词： shock interferometry delay

Position Control Optimization of Aerodynamic Brake Device for High-speed Trains

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Chinese Journal of Mechanical Engineering 2014年第2期27卷 287-295页

作者： zuo Jianyong luo Zhuojun CHEN Zhongkai Institute of Railway and Urban Mass Transit Tongji University

The aerodynamic braking is a clean and non-adhesion braking, and can be used to provide extra braking force during high-speed emergency braking. The research of aerodynamic braking has attracted more and more attentions in recent years. However, most researchers in this field focus on aerodynamic effects and seldom on issues of position control of the aerodynamic braking board. The purpose of this paper is to explore position control optimization of the braking board in an aerodynamic braking prototype. The mathematical models of the hydraulic drive unit in the aerodynamic braking system are analyzed in detail, and the simulation models are established. Three control functions--constant, linear, and quadratic--are explored. Two kinds of criteria, including the position steady-state error and the acceleration of the piston rod, are used to evaluate system performance. Simulation results show that the position steady state-error is reduced from around 12-2 mm by applying a linear instead of a constant function, while the acceleration is reduced from 25,71-3.70 m/s2 with a quadratic control function. Use of the quadratic control function is shown to improve system performance. Experimental results obtained by measuring the position response of the piston rod on a test-bench also suggest a reduced position error and smooth movement of the piston rod. This implies that the acceleration is smaller when using the quadratic function, thus verifying the effectiveness of control schemes to improve to system performance. This paper proposes an effective and easily implemented control scheme that improves the position response of hydraulic cylinders during position control.

关键词： high-speed train aerodynamic brake hydraulic position control optimization.

Almost sure limit theorem for the maximum of a class of quasi-stationary sequences

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Applied Mathematics(A Journal of Chinese Universities) 2014年第1期29卷 44-52页

作者： ZHUANG guang-ming PENG zuo-xiang School of Mathematical Sciences Liaocheng University School of Automation Nanjing University of Science and Technology School of Mathematics and Statistics Southwest University

This paper investigates the problem of almost sure limit theorem for the maximum of quasi-stationary sequence based on the result of Turkman and Walker. We prove an almost sure limit theorem for the maximum of a class of quasi-stationary sequence under weak dependence conditions of D （uk, un） and αtm,ln = 0 （（log log n）-（1＋ε））.

关键词： quasi-stationary sequence maximum limit distribution almost sure central limit theorem

Effects of PPARg agonist pioglitazone on rat hepatic fibrosis

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World Journal of Gastroenterology 2004年第7期10卷 1047-1051页

作者： guang-JinYuan Ming-LiangZhang zuo-JiongGong DepartmentofInfectiousDiseases RenminHospitalofWuhanUniversityWuhan430060HubeiProvinceChina DepartmentofGastroenterology theSecondAffiliatedHospitalofNanhuaUniversityHengyang421001HunanProvinceChina

AIM: To investigate effects of pioglitazone on rat hepatic fibrosis and to explore its mechanism. METHODS: Rat hepatic fibrosis was induced by carbontet. achloride (CCI4). Forty Sprague-Dawley rats were divided randomly into 4 groups: control, model, and two treatment (PⅠ, PⅡ) groups. Except for rats in control group, all rats were given subcutaneous injection of 400 mL/L CCI4, twice a wk for 8 wk. Rats in PⅠ and PⅡ groups were also treated with pioglitazone of 3 mg/kg, daily via gastrogavage beginning on the 1^st day and at the end of the 2^nd week, administration of CCI4 respectively. Liver functions (ALT, AST), serum fibrotic markers (HA, LN, PCIII) and hepatic hydroxyproline (HP) concentration were determined respectively. Histochemical staining of formalin-fixed liver sections with HE, Masson-Trichrome, and immunohistochemical staining for m-smooth muscle actin (α-SMA) were performed. Modified Knodell and Chevallier semi-quantitative scoring system (SSS) was used to evaluate necroinflammatory activity and fibrosis degree. RESULTS: Compared with model group, pioglitazone significantly reduced the serum levels of ALT, AST, HA, LN and PCⅢ (P<0.05 or <0.01). The HP concentrations in PⅠ(210.90±24.07 μg/g), and PⅡ (257.36±30.55 μg/g) groups were also lower than those in model group (317.80±36.44) μg/g) (P<0.01). Histologic examination showed that PⅠ and PⅡ groups had milder hepatocellular degeneration, necrosis and infiltration of inflammatory cells, and thinner or less fibrotic septa than did model group. The scores for necroinflammation in P (2.80±1.03), and PⅡ (3.00±1.05) groups were significantly reduced as compared with model group (4.88±2.30) (P<0.05 or <0.01); the fibrosis scores in PⅠ (3.40±1.65), and PⅡ (4.60±1.35) groups were also markedly lower than those in model group (7.00±3.21) (P<0.05 or <0.01). Immunohistochemical staining showed that expression of α-SMA in PⅠ and PⅡ groups was ameliorated dramatically compared with model group. CONCLUSION: PPARγ, ag

关键词：肝纤维化动物实验四氯化碳慢性肝病炎症反应过氧化物酶增殖活性受体

Adaptive Control of Discrete-time Nonlinear Systems Using ITF-ORVFL

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IEEE/CAA Journal of Automatica Sinica 2022年第3期9卷 556-563页

作者： Xiaofei Zhang Hongbin Ma Wenchao zuo Man luo School of Automation Beijing Institute of TechnologyBeijing 100081 School of Vehicle and Mobility Tsinghua UniversityBeijing 100084China School of Automation Beijing Institute of Technologyand also with the State Key Laboratory of Intelligent Control and Decision of Complex Systems(Beijing Institute of Technology)Beijing 100081China School of Automation Beijing Institute of TechnologyBeijing 100081and he is with Beijing Institute of Electronic System EngineeringBeijing 100854China School of Automation Beijing Institute of TechnologyBeijing 100081and she is with Ant GroupBeijing 310013China

Random vector functional ink(RVFL)networks belong to a class of single hidden layer neural networks in which some parameters are randomly *** network structure in which contains the direct links between inputs and outputs is unique,and stability analysis and real-time performance are two difficulties of the control systems based on neural *** this paper,combining the advantages of RVFL and the ideas of online sequential extreme learning machine(OS-ELM)and initial-training-free online extreme learning machine(ITFOELM),a novel online learning algorithm which is named as initial-training-free online random vector functional link algo rithm(ITF-ORVFL)is investigated for training *** link vector of RVFL network can be analytically determined based on sequentially arriving data by ITF-ORVFL with a high learning speed,and the stability for nonlinear systems based on this learning algorithm is *** experiment results indicate that the proposed ITF-ORVFL is effective in coping with nonparametric uncertainty.

关键词： Adaptive control initial-training-free online learning algorithm random vector functional link networks

Fault-tolerant FADS system development for a hypersonic vehicle via neural network algorithms

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Theoretical & Applied Mechanics Letters 2023年第5期13卷 357-366页

作者： Qian Wan Minjie Zhang guang zuo Tianbo Xie LandSpace Technology Corporation Ltd.H1 Zhonghang Intl Plaza 13 Ronghua South RoadBeijing 100176China Department of Aerospace and Mechanical Engineering University of Southern CaliforniaLos AngelesCA 90089-1189USA

Hypersonic vehicles suffer from extreme aerodynamic heating during flights, especially around the area of leading edge due to its small curvature. Therefore, flush air data sensing(FADS) system has been developed to perform accurate measurement of the air data parameters. In the present study, the method to develop the FADS algorithms with fail-operational capability for a sharp-nosed hypersonic vehicle is provided. To be specific, the FADS system implemented with 16 airframe-integrated pressure ports is used as a case study. Numerical simulations of different freestream conditions have been conducted to generate the database for the FADS targeting in 2 ≤ Ma ≤ 5 and 0 km ≤ H ≤ 30 km. Four groups of neural network algorithms have been developed based on four different pressure port configurations, and the accuracy has been validated by 280 groups of simulations. Particularly, the algorithms based on the 16-port configuration show an excellent ability to serve as the main solver of the FADS, where 99. 5% of the angle-of-attack estimations are within the error band ±0. 2°. The accuracy of the algorithms is discussed in terms of port configuration. Furthermore, diagnosis of the system health is present in the paper. A fault-tolerant FADS system architecture has been designed, which is capable of continuously sensing the air data in the case that multi-port failure occurs, with a reduction in the system accuracy.

关键词： FADS System Hypersonic vehicle Neural network Numerical simulation Fault detection Redundancy management

A comparative study of fuzzy weights of evidence and random forests for mapping mineral prospectivity for skarn-type Fe deposits in the southwestern Fujian metallogenic belt, China

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Science China Earth Sciences 2016年第3期59卷 556-572页

作者： ZHANG Zhen Jie zuo Ren guang XIONG Yi Hui School of Earth Sciences and Resources China University of Geosciences State Key Laboratory of Geological Processes and Mineral Resources China University of Geosciences

Recent studies have pointed out that the widespread iron deposits in southwestern Fujian metallogenic belt(SFMB)(China) are skarn-type deposits associated with the Yanshanian granites. There is still excellent potential for mineral exploration because large areas in this belt are covered by forest. A new predictive model for mapping skarn-type Fe deposit prospectivity in this belt was developed and focused on in this study, using five criteria as evidence:(1) the contact zones of Yanshanian granites(GRANITE);(2) the contact zones within the late Paleozoic marine sedimentary rocks and the carbonate formations(FORMATION);(3) the NE-NNE-trending faults(FAULT);(4) the zones of skarn alterations(SKARN); and(5) the aeromagnetic anomaly(AEROMAGNETIC). The fuzzy weights of evidence(FWof E) method, developed from the classical weights of evidence(Wof E) and based on fuzzy sets and fuzzy probabilities, could provide smaller variances and more accurate posterior probabilities and could effectively minimize the uncertainty caused by omitted or wrongly assigned data and be more flexible than the Wof E. It is an efficient and widely used method for mineral potential mapping. Random forests(RF) is a new and useful method for data-driven predictive mapping of mineral prospectivity method, and needs further scrutiny. Both prospectivity results respectively using the FWof E and RF methods reveal that the prediction model for the skarn-type Fe deposits in the SFMB is successful and efficient. Both methods suggested that the GRANITE and FORMATION are the most valuable evidence maps, followed by SKARN, AEROMAGNETIC, and FAULT. This is coincident with the skarn-type Fe deposit mineral model in the SFMB. The unstable performance experienced when FORMATION was omitted might indicate that the highest uncertainty and risk in follow-up exploration is related to the sequences. In addition, the performance of the RF method for the skarn-type Fe deposits prospectivity in the SFMB is better than

关键词： Mineral prospectivity mapping Fuzzy weights of evidence Random forest Skarn-type Fe Makeng deposit

Crystallization behavior of F-free mold fluxes

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International Journal of Minerals,Metallurgy and Materials 2011年第2期18卷 150-158页

作者： zuo-tai Zhang guang-hua Wen Ying-yi Zhang College of Engineering Peking University Beijing 100871 China College of Materials Science and Engineering Chongqing University Chongqing 400044 China

The time-temperature-transformation （TTT） diagrams of F-free mold fluxes was constructed using single hot thermocouple technique （SHTT） and confocal scanning laser microscopy （CSLM） to study the crystallization behavior of F-free mold fluxes. The tendency of crystallization is found to increase whereas the incubation time decreases with increasing basicity. Zirconia addition enhances the crystallization tendency due to its limited solubility in the slag melt and the solid particles acting as nucleation sites. Pseudo-wollastonite is found to precipitate in the slag with low basicity （CS-1 and CS-2）, kilchoanite and larnite are formed with further increasing basicity （CS-3）, and larnite is finally formed as the basicity beyond unit （CS-4）. The crystal morphology changes with varying compositions and isothermal temperatures. The measured growth rate is found to be linear with time under isothermal conditions and decreases with increasing isothermal temperature.

关键词： continuous casting mold fluxes crystallization zirconia crystal growth

Impact wear properties of dissimilar joints between bainitic frogs and pearlite rails

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Journal of Iron and Steel Research International 2024年第1期31卷 275-287页

作者： Pin-yong Zeng Chun-guang zuo Xiao-yu Zhang Wei Li Tribology Research Institute Southwest Jiaotong UniversityChengdu610031SichuanChina

The impact wear behavior and damage mechanism of dissimilar welded joints between U26Mn frog and U75 V rail before and after normalizing treatment were studied by cyclic impact *** experiment indicated that the impact wear volume of the joints increased with the increasing number of impact *** main wear mechanisms include pitting wear,mild fatigue wear,delamination wear,and fatigue wear,and plastic deformation was the primary impact wear *** them,fatigue wear had the greatest influence on wear volume,while other wear mechanisms had limited *** impact wear resistance of the base material was better than that of the heat-affected *** treatment was beneficial to improving the impact wear resistance of welded joints owing to its effect to promote pearlite recovery,grain refinement,and uniform distribution of *** martensite generated in the rail welded joints aggravated the impact wear damage to the materials,which should be avoided.

关键词： Dissimilar welded joint Impact wear Bainitic steel Damage mechanism Wear rate