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Numerical analysis for the matching of the core driven compression system in a double bypass engine

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航空动力学报 2011年第5期26卷 1066-1076页

作者： ZHANG Xin LIU bao-jie National Key Laboratory of Science and Technology on Aero-Engine Aero-thermodynamics School of Jet Propulsion Beijing University of Aeronautics and Astronautics Beijing 100191 China

The numerical analysis for the matching of the core driven compression system in a double bypass variable cycle engine was presented in this *** system consists of a one-stage-core driven fan stage(CDFS),an inner bypass duct and a five-stage high pressure compressor(HPC),providing two basic operating modes: the single bypass mode and the double bypass *** vanes are necessary to realize the mode switch of the *** correct matching in the double bypass mode requires a proper combination of the mass flow,total pressure ratio and blade *** work capacity of the system decreases in the double bypass mode and the pressure ratio tends to decrease more for the CDFS and the front stages of the *** overall system efficiency is higher in the double bypass *** radial distributions of aerodynamic parameters are similar in different *** notable redistribution of mass flow downstream the CDFS in the single bypass mode leads to strong radial flows and additional mixing *** absolute flow angles into the inner bypass increase for the inner span and decrease for the outer span when the system is switched from the single bypass mode to the double bypass mode.

关键词： numerical analysis aerodynamic double bypass variable cycle engine core driven compression system core driven fan stage operating mode

Observed displacement data-based identification method of deformation time-varying effect of high concrete dams

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Science China(Technological Sciences) 2018年第6期61卷 906-915页

作者： WANG ShaoWei GU ChongShi bao TengFei l School of Environmental and Safety Engineering Changzhou University Changzhou 213164 China State Key Laboratory of Hydrology-Water Resources andHydraulic Engineering Hohai University Nanjing 210098 China

The long-term safety of high concrete dams has become the focus and central issues of public attention. Deformation is an actual comprehensive reflection of concrete dams. Especially the deformation time-varying effect, is a key index for evaluating the structural behavior, health status, and their evolution of a concrete dam in long-term service. In this paper, causing factors of the deformation time-varying effect of concrete dams were analyzed, and the time-varying effect was divided into two parts, which are the inherent time-varying effect and the time-varying effect caused by the change of dam structural performance. Then, based on the observed dam displacement and the wavelet multi-resolution analysis, causal models for identifying the later deformation time-varying effect and the identification process were proposed. Finally, the efficiency and rationality of the proposed method were verified by two actual concrete dams with runoff reservoir and regulatory reservoir.

关键词： high concrete dam deformation time-varying effect causing analysis identification method

Weighted approximation of functions with singularities by Bernstein operators

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2008年第10期9卷 1451-1456页

作者： bao-rong WEI Yi ZHAO Department of Mathematics Hangzhou Normal University Hangzhou 310036 China Institute of Mathematics Hangzhou Dianzi University Hangzhou 310018 China

As an important type of polynomial approximation, approximation of functions by Bernstein operators is an important topic in approximation theory and computational theory. This paper gives global and pointwise estimates for weighted approximation of functions with singularities by Bernstein operators. The main results are the Jackson＇s estimates of functions f∈ （Wwλ）2 andre Cw, which extends the result of （Della Vecchia et al., 2004）.

关键词： Bemstein operators Functions with singularities Weighted approximation Pointwise estimates

The idealist and pragmatist view of qi in tai chi and qigong:A narrative commentary and review

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Journal of Integrative Medicine 2020年第5期18卷 363-368页

作者： George Chengxi bao Section of Hospital Medicine Division of General Internal MedicineDepartment of MedicineWeill Cornell MedicineNew York 10038USA

Qi, often translated as ‘‘vital energy," is a central concept in tai chi and qigong that has puzzled physicians, scientists, and people in the West. To date, qi is not falsifiable by the scientific method and thus cannot be subject to scientific inquiry, leading many to criticize it as ‘‘pseudoscientific." Even as medical research reveals the health benefits of tai chi and qigong, many wonder how to treat this seemingly outdated concept when promoting these meditative practices. While some tai chi and qigong practitioners insist on the existence of qi, more skeptical thinkers suggest that a scientific understanding should replace this ‘‘superstitious" idea. Integrative health professionals must be equipped to discuss this concept intelligently by considering a couple of subtle, clarifying points often missing from the ***, science's inability to verify qi's existence does not affirm its nonexistence. In fact, under the philosophical system of idealism, qi might not be said to be less real than things that are verifiable by ***, under the instrumental and pragmatic view of science, health professionals should be cautious not to declare what is metaphysically real or unreal but instead what is useful and not useful. Second,even though qi may be pseudoscientific, it remains useful and indispensable to the correct practice of tai chi and qigong. Tai chi and qigong practitioners routinely visualize and perceive the flow of qi to guide their movements, breathing, and mental activity. As such, qi and related metaphysical concepts serve as a useful mental model during practice, and belief in them may be viewed as an ‘‘expedient means" to achieve one's health goals.

关键词： Integrative medicine Tai chi Qigong Pseudoscience Qi Philosophy

Source and Control of Nitrogen for X70 Pipeline Steel

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Journal of Iron and Steel Research International 2016年第7期23卷 647-654页

作者： Min WANG Yan-ping bao State Key Laboratory of Advanced Metallurgy University of Science and Technology Beijing School of Metallurgical and Ecological Engineering University of Science and Technology Beijing

The effects of some key factors on nitrogen absorption during the smelting process of X70 pipeline steel were studied,and the source of nitrogen pick-up was analyzed to find the bottleneck for nitrogen control.A series of measures were put forward to decrease the nitrogen *** results indicated that an exponential relationship existed between the nitrogen absorption index and the free oxygen in molten *** absorption index could decrease below 0.3when free oxygen in molten steel was above 100×10^（-6） after *** low sulfur killed steel,the nitrogen absorption ratio and sulfur content satisfied a linear relationship with a slope *** free-oxygen and sulfur were beneficial to the deep desulfurization during vacuum *** contradiction of high desulfurization ratio and low nitrogen pick-up during LF process could be resolved by skimming oxidizing slag after tapping and making new high basicity top *** optimization,the average content of nitrogen in final product decreased from 46×10（-6）to 35×10（-6）.

关键词： nitrogen control nitrogen absorption surface activity element X70 pipeline steel

Effect of Fe ion implantation on tribological properties and Raman spectra characteristics of diamond-like carbon film

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Nuclear Science and Techniques 2004年第2期15卷 95-98页

作者： JIAWen-bao SUNZhuo ShanghaiUniversityofEngineeringScience Shanghai200336 CenterforFunctionalNanomaterialsandDevices EastChinaNormalUniversityShanghai200062

Fe ions in the fluence range of 2×1015 to 1×1017 cm-2 were implanted into diamond-like carbon (DLC) thin film of 100 nm thick, which were deposited on silicon substrate by plasma enhanced chemical vapor deposition. Effects of Fe ion implantation on microstructure and friction coefficient of the DLC were studied. With increasing Fe ion fluence, friction coefficient of the DLC film increased as compared with that of DLC without implantation, and then decreased. The Raman spectra characteristics also show a dependence on the Fe ion fluence. With increasing the ion fluence, the sp2 bonding increased in the DLC film, resulting in the decrease of friction coefficient of the film af- ter implantation. Substantial surface roughness was also measured.

关键词：铁离子类金刚石碳薄膜摩擦学性质 Raman光谱特性物理气相沉积等离子体增强化学气相沉积

Fabrication of green one-part geopolymer from silica-rich vanadium tailing via thermal activation and modification

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International Journal of Minerals,Metallurgy and Materials 2022年第1期29卷 177-184页

作者： Shenxu bao Yongpeng Luo Yimin Zhang Hubei Key Laboratory of Mineral Resources Processing and Environment Wuhan University of TechnologyWuhan 430070China School of Resources and Environmental Engineering Wuhan University of TechnologyWuhan 430070China State Environmental Protection Key Laboratory of Mineral Metallurgical Resources Utilization and Pollution Control Wuhan University of Science and TechnologyWuhan 430081China Hubei Collaborative Innovation Center for High Efficient Utilization of Vanadium Resources Wuhan University of Science and TechnologyWuhan 430081China

The aim of this investigation was to prepare geopolymeric precursor from vanadium tailing(VT)by thermal activation and *** activation,a homogeneous blend of VT and sodium hydroxide was calcinated at an elevated temperature and then modified with metakaolin to produce a geopolymeric *** the thermal activation,the VT was corroded by sodium hydroxide and then sodium silicate formed on the particle *** water was added,the sodium silicate coating dissolved to release silicon species,which created an alkaline solution *** metakaolin then dissolved in the alkaline environment to generate aluminum species,which was followed by *** VT particles were connected by a gel produced during geopolymerization,which yielded a geopolymer with excellent mechanical *** investigation not only improves the feasibility of using geopolymer technology for large-scale and in-situ applications,but also promotes the utilization of VT and other silica-rich solid wastes.

关键词： vanadium tailing thermal activation geopolymeric precursor compressive strength leaching behavior

Identifying Influential Spreaders in Complex Networks by Considering the Impact of the Number of Shortest Paths

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Journal of Systems Science & Complexity 2021年第6期34卷 2168-2181页

作者： LUAN Yangyang bao Zhongkui ZHANG Haifeng School of Mathematical Science Anhui UniversityHefei 230601China

The study on how to identify influential spreaders in complex networks is becoming increasingly *** studies demonstrate that considering the shortest path length can improve the accuracy of identification,but which ignore the influence of the number of shortest *** many cases,even though the shortest path length of two nodes is rather larger,their interaction influence is also significant if the number of shortest paths between them is *** by this fact,the authors propose an improved centrality index(ICC)based on well-known closeness centrality and a semi-local iterative algorithm(semi-IA)to study the impact of the number of shortest paths on the identification of the influential *** comparing with several traditional centrality indices,such as degree centrality,k-shell decomposition,betweenness centrality and eigenvector centrality,the experimental results on real networks indicate that the ICC index and semi-IA have a better performance,regardless of the identification capability or the resolution.

关键词： Complex networks influential spreader number of shortest paths

Electrochemical behavior and corrosion resistance of IrO2–ZrO2 binary oxide coatings for promoting oxygen evolution in sulfuric acid solution

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International Journal of Minerals,Metallurgy and Materials 2020年第2期27卷 264-273页

作者： bao Liu Shuo Wang Cheng-yan Wang bao-zhong Ma Yong-qiang Chen School of Metallurgical and Ecological Engineering University of Science and Technology BeijingBeijing 100083China Beijing Key Laboratory of Rare and Precious Metals Green Recycling and Extraction University of Science and Technology BeijingBeijing 100083China

In this study,we prepared Ti/IrO2–ZrO2 electrodes with different ZrO2 contents using zirconium-n-butoxide(C16H36O4Zr)and chloroiridic acid(H2IrCl6)via a sol–gel *** explore the effect of ZrO2 content on the surface properties and electrochemical behavior of electrodes,we performed physical characterizations and electrochemical *** obtained results revealed that the binary oxide coating was composed of rutile IrO2,amorphous ZrO2,and an IrO2–ZrO2 solid *** IrO2–ZrO2 binary oxide coatings exhibited cracked structures with flat regions.A slight incorporation of ZrO2 promoted the crystallization of the active component ***,the crystallization of IrO2 was hindered when the added ZrO2 content was greater than 30at%.The appropriate incorporation of ZrO2 enhanced the electrocatalytic performance of the pure IrO2 *** Ti/70at%IrO2–30at%ZrO2 electrode,with its large active surface area,improved electrocatalytic activity,long service lifetime,and especially,lower cost,is the most effective for promoting oxygen evolution in sulfuric acid solution.

关键词： electrode IrO2-ZrO2 oxygen evolution reaction electrochemical behavior corrosion resistance