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Influence Factors for Impact Actions and Transient Trajectories of Fan Blades after Fan Blade Out in Typical 2-Shaft High Bypass Ratio Turbofan Engine

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Journal of Thermal Science 2022年第1期31卷 96-110页

作者： xu xue LI Hongxin FENG Guoquan Shenyang Engine Research Institute Aero Engine Corporation of ChinaShenyang 110015China Corporation Headquarter Aero Engine Corporation of ChinaBeijing 100097China

To enhance the understanding of design characters, which have prominent influences during the fan blade out event, a simplified geometrical and dynamic analysis method was derived, and a typical 2-shaft high bypass ratio turbofan engine was selected and modeled. Based on analytical deriving and engineering experience learned from the real engine failure case, three determinative impact actions were recognized from the fan blade out process. The transient trajectories of these impact actions were researched in analytical method, and then thickness of acoustic lining, quantity of fan blades and threshold load of structural fuse were analyzed as key design characters. 36 serialized fan blade out transient dynamic simulations were conducted by using the 2-shaft high bypass ratio turbofan engine model within different combinations of the three key design factors. The results from geometrical and dynamic analysis matched mainly well with the results from simulations. Characteristic phenomenon in simulation can be explained theoretically. Five conclusions can be summarized from these results. (1) If thickness fan acoustic lining was thinner, the deviation between simplified analytical calculation and simulation were not outstanding to predict Blade-Casing the first impact time and angular position. (2) An appropriate thickness of acoustic lining could make a lower impact stress of fan casing at the first impact. (3) Different thickness of acoustic linings leaded to two impact modes for blade 2, which were tip impact and root impact. (4) Different impact conditions between blade 1 and blade 2 caused remarkable speed components distinction of blade 1, and leaded to a wide range of transient trajectory of blade 1 during FBO event. (5) Thicker acoustic lining in this research can usually find the porper threshold loads setting, which can give a satisfactory outbound vibration. Two details were raised for further research, which were impact behavior of composite material fan bl

关键词： fan blade out transient trajectory design character structural fuse high bypass ratio turbofan

Initial Development of a Novel Amphibious Robot with Transformable Fin-Leg Composite Propulsion Mechanisms

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Journal of Bionic Engineering 2013年第4期10卷 434-445页

作者： Shiwu Zhang xu Liang Lichao xu min xu Department of Precision Machinery and Precision Instrumentation University of Science and Technology of China Hefei 230026 P. R. China

Amphibious robots are very attractive for their broad applications in resource exploration, disaster rescue, and recon- naissance. However, it is very challenging to develop the robots for their complex, amphibious working environments. In the complex amphibious environment, amphibious robots should possess multi-capabilities to walk on rough ground, maneuver underwater, and pass through transitional zones such as sandy and muddy terrain. These capabilities require a high-performance propulsion mechanism for the robots. To tackle a complex task, a novel amphibious robot （AmphiHex-I） with,transformable fin-leg composite propulsion mechanisms is developed. With the fin-leg composite propulsions, AmphiHex-I can walk on rough and soft substrates and swim in water with many maneuvers. This paper presents the structural design of the transformable fin-leg propulsion mechanism and its driving module. A hybrid model is used to explore the dynamics between the trans- formable legs and transitional environment such as granular medium. The locomotion performances of legs with various ellip- tical shapes are analyzed, which is verified by the coincidence between the model predictions and the simulation results. Further, an orthogonal experiment is conducted to study the locomotion performance of a two-legged platform walking with an asyn- chronous gait in the sandy and muddy terrain. Finally, initial experiments of AmphiHex-I walking on various lands and swimming in water are implemented. These results verify that the transformable fin-leg mechanisms enable the amphibious robot to pass through a complex, amphibious working environment.

关键词： amphibious robot transformable fin-leg composite propulsion mechanism amphibious environment

Partitioning Complete Graphs by Heterochromatic Trees

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Acta Mathematicae Applicatae Sinica 2012年第4期28卷 625-630页

作者： Ze-min JIN xue-liang LI Department of Mathematics Zhejiang Normal University Center for Combinatorics and LPMC Nankai University

A heterochromatie tree is an edge-colored tree in which any two edges have different colors. The heterochromatic tree partition number of an r-edge-colored graph G, denoted by tr （G）, is the minimum positive integer p such that whenever the edges of the graph G are colored with r colors, the vertices of G can be covered by at most p vertex-disjoint heterochromatic trees. In this paper we determine the heterochromatic tree partition number of r-edge-colored complete graphs. We also find at most tr（Kn） vertex-disjoint heterochromatic trees to cover all the vertices in polynomial time for a given r-edge-coloring of Kn.

关键词： edge-colored graph heterochromatic tree partition

Phosphate enrichment mechanism in CaO–SiO_2–FeO–Fe_2O_3–P_2O_5 steelmaking slags with lower binary basicity

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International Journal of minerals,Metallurgy and Materials 2016年第5期23卷 520-533页

作者： Jin-yan Li Mei Zhang min Guo xue-min Yang State Key Laboratory of Advanced Metallurgy School of Metallurgical and Ecological Engineering University of Science and Technology Beijing Beijing 100083China Key Laboratory of Green Process and Engineering Institute of Process Engineering Chinese Academy of Sciences Beijing 100190 China

The addition of silica to steelmaking slags to decrease the binary basicity can promote phosphate enrichment in quenched slag samples. In this study, we experimentally investigated phosphate enrichment behavior in CaO-SiO2-FeO-Fe203-P205 slags with a P205 content of 5.00% and the binary basicity B ranging from 1.0 to 2.0, where the （%Fe/O）/（%CaO） mass percentage ratio was maintained at 0.955. The experimental results are explained by the defined enrichment degree c, of solid solution 2CaO·SiO2-3CaO·P205 （C2S-C3P）, where R_C2S-C3P is a component of the developed ion and molecule coexistence theory （IMCT）-Ni model for calculating the mass action concentrations Ni of structural units in the slags on the basis of the IMCT. The asymmetrically inverse V-shaped relation be- tween phosphate enrichment and binary basicity B was observed to be correlated in the slags under applied two-stage cooling conditions. The maximum content of PROs in the C2S-C3P solid solution reached approximately 30.0% when the binary basicity B was controlled at 1.3.

关键词： phosphates enrichment mechanisms steelmaking slags basicity

Compound extreme events in Yarlung Zangbo River Basin from 1977 to 2018

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Water Science and Engineering 2023年第1期16卷 36-44页

作者： Zong-xue xu Rui Zhang College of Water Sciences Beijing Normal UniversityBeijing 100875China Beijing Key Laboratory of Urban Hydrological Cycle and Sponge City Technology Beijing 100875China

Extreme climate events threaten human health,economic development,and *** studies have been conducted on extreme precipitation and temperature changes in the Yarlung Zangbo River Basin(YZRB).However,little attention has been paid to compound climate *** this study,the variations of wet/warm compound extreme events in summer and dry/cold compound extreme events in winter over the past 42 years in the YZRB were investigated using eight extreme climate indices that were estimated using monthly temperature and precipitation *** results showed that the numbers of frost days and ice days tended to decrease on the spatiotemporal scale,while the maximum values of daily maximum temperature and daily minimum temperature exhibited increasing *** frequency of wet/warm compound extreme events was significantly higher from 1998 to 2018 than from 1977 to ***/cold compound extreme events became less frequent from 1998 to 2018 than from 1977 to *** rate of increase of wet/warm compound extreme events was about ten times the absolute rate of decrease of dry/cold compound extreme *** regard to the spatial pattern,the frequency of wet/warm compound extreme events increased significantly in almost all parts of the YZRB,while that of dry/cold compound extreme events decreased across the *** study helps to improve our understanding of the changes in compound precipitation and temperature extremes in the YZRB from a multivariable perspective.

关键词： Climate change Extreme events Precipitation Temperature Yarlung Zangbo River Basin

Influence of drought hardening on the resistance physiology of potato seedlings under drought stress

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Journal of Integrative Agriculture 2018年第2期17卷 336-347页

作者： ZHANG Shu-han xu xue-feng SUN Ye-min ZHANG Jun-lian LI Chao-zhou Gansu Key Laboratory of Crop Genetics & Germplasm Enhancement College of Life Sciences and Technology Gansu Agricultural University College of Horticulture Gansu Agricultural University

In this paper, the influence of drought hardening on the growth, development, resistance physiology, leaf microstructure and stomatal behavior of potato seedlings under drought stress was studied, and the mechanism of drought hardening improvement of potato seedling drought resistance was elucidated. We found that drought stress had several adverse effects on potato seedlings, yet drought hardening alleviated the decrease in relative water content（RWC）, net photosynthetic rate（Pn） and chlorophyll content and inhibited the increase in relative electric conductivity and malondialdehyde（MDA） content. Compared with contrast seedlings, drought-hardened seedlings also had enhanced root vigor, increased antioxidant enzyme activity and higher levels of abscisic acid（ABA）, proline（Pro）, soluble sugars and polyamines（PAs） under drought stress. In addition, the stomatal density of potato seedling leaves increased significantly, while the leaf area, stomatal size and stomatal aperture decreased with drought hardening treatment. These changes led to reduced leaf transpiration rate（Tr） and improved water utilization efficiency（WUE）. The changes in leaf microstructure also had a positive effect on the drought resistance of the drought-hardened potato seedlings. So it can be concluded that through increasing the content of some endogenous hormones, osmotic regulatory substances and the activities of antioxidant enzymes, the resistance physiology of drought-hardened potato seedlings was enhanced.

关键词： drought drought hardening potato resistance physiology

Dual Z-scheme Bi_(3)TaO_(7)/Bi_(2)S_(3)/SnS_(2)photocatalyst with high performance for Cr(Ⅵ)reduction and TC degradation under visible light irradiation

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Rare Metals 2022年第7期41卷 2417-2428页

作者： Jing-Jing xu Hao-Yu Gu min-Dong Chen xue-Ping Li Hong-Wen Zhao Hong-Bin Yang Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control Nanjing 210044China Collaborative Innovation Center of Atmospheric Environment and Equipment Technology Nanjing 210044China Jiangsu Engineering Technology Research Center of Environmental Cleaning Materials Nanjing 210044China School of Environmental Science and Engineering Nanjing University of Information Science and TechnologyNanjing 210044China Nanyang Technological University Singapore 639798Singapore

Ternary direct dual Z-scheme Bi_(3)T_(a)O_(7)/Bi_(2)S_(3)/SnS_(2) photocatalyst was successfully prepared by hydrothermal *** composite photocatalysts exhibited high photocatalytic performance on both Cr(Ⅵ)reduction and tetracycline(TC)degradation under the irradiation of visible *** results manifested that the photogenerated charge transfer efficiency was improved after forming the dual Z-scheme *** a result,the composite catalysts exhibited higher photocat-alytic degradation efficiency than the corresponding single *** apparent rate constant(k)value of the best sample BBS-3 for TC degradation was 0.0403 min^(-1),which was 40 times,8 times,and 18 times higher than that of single *** the k value of BBS-3 for the Cr(Ⅵ)reduction was 0.0249 min^(-1),it was about 23 times,7 times,and 18 times that of single *** experiments indicated that the BBS-3 had good photocat-alytic ***,the possible mechanism on Cr(Ⅵ)reduction and TC degradation was proposed based on the experimental results.

关键词： Photocatalysis Dual Z-scheme Heterojunction Heavy metal Organic pollutant

Protective Effect of Angiotensin(1-7) on Silicotic Fibrosis in Rats

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Biomedical and Environmental Sciences 2019年第6期32卷 419-426页

作者： ZHANG Bo Nan xu Hong GAO xue min ZHANG Gui Zhen ZHANG Xin YANG Fang School of Public Health North China University of Science and Technology Tangshan 063210 Hebei China Hebei Key Laboratory for Organ Fibrosis Medical Research Center North China University of Science and Technology Tangshan 063210 Hebei China Hebei Key Laboratory for Chronic Diseases Tangshan Key Laboratory for Clinical and Basic Research on Chronic Diseases School of Basic Medical Sciences North China University of Science and Technology Tangshan 063210 Hebei China Basic Medical College Hebei Medical University Shijiazhuang 050017 Hebei China

Objective Silicosis, caused by inhalation of silica dust, is the most serious occupational disease in China and the aim of present study was to explore the protective effect of Ang(1-7) on silicotic fibrosis and myofibroblast differentiation induced by Ang II. Methods HOPE-MED 8050 exposure control apparatus was used to establish the rat silicosis model. Pathological changes and collagen deposition of the lung tissue were examined by H.E. and VG staining, respectively. The localizations of ACE2 and α-smooth muscle actin(α-SMA) in the lung were detected by immunohistochemistry. Expression levels of collagen type I, α-SMA, ACE2, and Mas in the lung tissue and fibroblasts were examined by western blot. Levels of ACE2, Ang(1-7), and Ang II in serum were determined by ELISA. Co-localization of ACE2 and α-SMA in fibroblasts was detected by immunofluorescence. Results Ang(1-7) induced pathological changes and enhanced collagen deposition in vivo. Ang(1-7) decreased the expressions of collagen type I and α-SMA and increased the expressions of ACE2 and Mas in the silicotic rat lung tissue and fibroblasts stimulated by Ang II. Ang(1-7) increased the levels of ACE2 and Ang(1-7) and decreased the level of Ang II in silicotic rat serum. A779 enhanced the protective effect of Ang(1-7) in fibroblasts stimulated by Ang II. Conclusion Ang(1-7) exerted protective effect on silicotic fibrosis and myofibroblast differentiation induced by Ang II by regulating ACE2-Ang(1-7)-Mas axis.

关键词： Silicosis Ang II Myofibroblasts Ang(1-7) A779

UNIFORMLY-STABLE FINITE ELEMENT METHODS FOR DARCY-STOKES-BRINKMAN MODELS

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Journal of Computational Mathematics 2008年第3期26卷 437-455页

作者： Xiaoping Xie Jinchao xu Guangri xue Yangtze Center of Mathematics and School of Mathematics Sichuan University Chengdu 610064 China Center for Computational Mathematics and Applications Mathematics Department The Pennsylvania State University PA 16802 USA

In this paper, we consider 2D and 3D Darcy-Stokes interface problems. These equations are related to Brinkman model that treats both Darcy＇s law and Stokes equations in a single form of PDE but with strongly discontinuous viscosity coefficient and zerothorder term coefficient. We present three different methods to construct uniformly stable finite element approximations. The first two methods are based on the original weak formulations of Darcy-Stokes-Brinkman equations. In the first method we consider the existing Stokes elements. We show that a stable Stokes element is also uniformly stable with respect to the coefficients and the jumps of Darcy-Stokes-Brinkman equations if and only if the discretely divergence-free velocity implies almost everywhere divergence-free one. In the second method we construct uniformly stable elements by modifying some well-known H（div）-conforming elements. We give some new 2D and 3D elements in a unified way. In the last method we modify the original weak formulation of Darcy-Stokes- Brinkman equations with a stabilization term. We show that all traditional stable Stokes elements are uniformly stable with respect to the coefficients and their jumps under this new formulation.

关键词： Darcy-Stokes equation Brinkman Finite element Uniformly stable