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A novel redox indicator based on relative abundances of c_(31) and c_(32) homohopanes in the Eocene lacustrine Dongying Depression, East china

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Petroleum Science 2022年第4期19卷 1494-1504页

作者： chong Jiang Hai-Ping Huang zheng Li Hong Zhang zheng Zhai School of Energy Resource China University of Geosciences(Beijing)Beijing100083China School of Geosciences Yangtze UniversityWuhanHubei430100China Department of Geoscience University of CalgaryCalgaryAlbertaT2N 1N4Canada Geology Scientific Research Institute of Shengli Oilfield company SinopecDongyingShandong 257015China

A suite of oils and bitumens from the Eocene Shahejie Formation(Es) in Dongying Depression was geochemically characterized to illustrate impact of source input and redox conditions on distributions of pentacyclic terpanes. The Es_(4) developed under highly reducing, sulfidic hypersaline conditions, while Es_(3) formed under dysoxic, brackish to freshwater conditions. Oils derived from Es_(4) are enriched in c_(32) homohopanes(c_(32) H), while those from Es_(3) are prominently enriched in c_(31) homohopanes(c_(31) H). The c_(32) H/c_(31) H ratio shows positive correlation with homohopane index(HHI), gammacerane index, and negative correlation with pristane/phytane ratio, and can be used to evaluate oxic/anoxic conditions during deposition. High c32 H/c_(31) H ratio(> 0.8) is an important characteristic of oils derived from anoxic environments, while low values(cate dysoxic conditions and extremely low values(cate strong oxic conditions. The c_(32) H/c_(31) H ratio can be applied for deposition condition diagnosis because carboxyl group of c_(32) hopanoic acids might be reduced to c_(32) homohopanes under anoxic conditions, and oxidized to c_(31) homohopane under oxic conditions. Advantages to use c_(32) H/c_(31) H ratio as redox condition proxy compared to the HHI and gammacerane indexes are wider valid maturity range,less sensitive to biodegradation influence and better differentiating reducing from oxic environments.

关键词： paper Biomarkers c_(32)/c_(31)homohopane ratio Redox conditions Dongying Depression

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Effects of long term aging on microstructure and properties of a tungsten bearing heat resistant alloy

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Journal of Iron and Steel Research International 2020年第4期27卷 477-487页

作者： Han-sheng Bao Gang Yang zheng-zong chen zheng-dong Liu Institute for Special Steels Central Iron and Steel Research InstituteBeijing 100081China

The effects of long-term aging at 700 and 750℃ on microstructure and mechanical properties of a new developed tungsten bearing heat-resistant alloy used for advanced ultra-supercritical power plant was investigated both experimentally and *** results showed that the mechanical properties maintained excellent stability after long-term aging at 700℃ for 10,000h,while the impact absorbing energy decreased sharply after 1000-h aging and then kept constant till 10,*** main precipitates after long-term aging at 700 and 750℃ were M23c6,Mc and homogeneous γ′-*** mass fraction of M23c6 carbides increased with increasing aging time,and M23c6 carbides precipitated in shape of chains and lamellas on grain *** slight decrease in Mc carbides during aging may be due to degradation *** weight fraction of γ′-phase increased with the aging time,and then changed little after 5000h;γ′-phase exhibited excellent microstructure stability and low coarsening rate during long-term aging at 700℃.However,the coarsening rate of γ′-phase was much higher at 750℃.

关键词： Tungsten Long-term aging Heat-resistant alloy gama′-phase coarsening rate

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Regulation of Hedgehog signaling by ubiquitination

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Frontiers in Biology 2015年第3期10卷 203-220页

作者： Elaine Y. c. Hsia Yirui Gui Xiaoyan zheng Department of Anatomy and Regenerative Biology George Washington University School of Medicine and Health SciencesWashington DC 20037 USA

The Hedgehog （Hh） signaling pathway plays crucial roles both in embryonic development and in adult stem cell function. The timing, duration and location of Hh signaling activity need to be tightly controlled. Abnormalities of Hh signal transduction lead to birth defects or malignant tumors. Recent data point to ubiquitination-related posttranslational modifications of several key Hh pathway components as an important mechanism of regulation of the Hh pathway. Here we review how ubiquitination regulates the localization, stability and activity of the key Hh signaling components.

关键词： Hedgehog signaling ubiquitination

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Two-dimensional d-πconjugated metal-organic framework based on hexahydroxytrinaphthylene

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Nano Research 2021年第2期14卷 369-375页

作者： zheng Meng Katherine A.Mirica Department of chemistry Burke Laboratory41 College Streety Dartmouth CollegeHanoverNH 03755USA

The development of new two-dimensional(2D)d-πconjugated metal-organic frameworks(MOFs)holds great promise for the construction of a new generation of porous and semiconductive *** paper describes the synthesis,structural characterization,and electronic properties of a new d-πconjugated 2D MOF based on the use of a new ligand 2,3,8,9,14,*** reticular self-assembly of this largeπ-conjugated organic building block with cu(II)ions in a mixed solvent system of 1,3-dimethyl-2-imidazolidinone(DMI)and H2 O with the addition of ammonia water or ethylenediamine leads to a highly crystalline MOF cu3(HHTN)2,which possesses pore aperture of 2.5 ***3(HHTN)2 MOF shows moderate electrical conductivity of 9.01×10^(-8)S·cm^(-1)at 385 K and temperature-dependent band gap ranging from 0.75 to 1.65 *** chemical oxidation by l2,the conductivity of cu3(HHTN)2 can be increased by 360 *** access to HHTN based MOF adds an important member to previously reported MOF systems with hexagonal lattice,paving the way towards systematic studies of structure-property relationships of semiconductive MOFs.

关键词： two-dimensional metal-organic framework(MOF) trinaphthylene conductive MOF

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Effect of erbium doping on phase composition, mechanical and thermal properties of ZrO_(2)-based ceramics

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Journal of Rare Earths 2022年第10期40卷 1628-1634页

作者： zheng cao Shengli An Xiwen Song School of Metallurgy and Ecological Engineering University of Science and Technology BeijingBeijing 100083China Inner Mongolia Key Laboratory of Advanced ceramic Materials and Devices Inner Mongolia University of Science and TechnologyBaotou O14010China School of Materials and Metallurgy Inner Mongolia University of Science and TechnologyBaotou 014010China

Er_(x)Ti_(0.1)Zr_(0.9-x)O_(2-1.5 x)(x=0.04,0.05,0.06,0.07,0.08) ceramics were synthesized by a solid-state reaction *** influence of the Er^(3+) addition on the phase composition,Vickers hardness,fracture toughness,and thermal conductivity of this ceramic material was *** X-ray diffraction results reveal that the c-ZrO_(2) content increases from 1.85 vol% to 33.89 vol%,and the percentage of t-ZrO_(2) decreases from 98.15 vol% to 66.11 vol% with the increase in Er^(3+) content from 4 mol% to 8 mol%.Moreover,the addition of Er^(3+) is beneficial to the volume expansion of the unit *** the same time,the incorporation of Er^(3+) weakens the coordination of oxygen ions around the metal cations,resulting in a corresponding decrease in the tetragonality of the t-ZrO_(2).The Vickers hardness and fracture toughness of the Er_(x)Ti_(0.1)Zr_(0.9-x)O_(2-1.5)_(x) ceramics show increasing and decreasing trends,*** thermal conductivity has a significant decline due to point defects caused by the Er^(3+) *** 8 ETZ ceramic exhibits the highest Vickers hardness(12.7 GPa),the lowest fracture toughness(7.6 MPa·m^(1/2)),and the lowest average thermal conductivity(1.85 W/(m·K)) in the temperature range of 200-1000℃.All of the above properties are higher than those of the Y_(2)O_(3)-stabilized ZrO_(2) ceramic.

关键词： Er_(2)O_(3) Phase composition Vickers hardness Fracture toughness Thermal conductivity Rare earths

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The quasi-triangular structures over Hom-ω-smash coproduct Hopf algebras

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Applied Mathematics(A Journal of chinese Universities) 2016年第2期31卷 219-236页

作者： zheng Nai-feng Department of Mathematics Ningbo University

Let （c,α） and （H, β） be Hom-bialgebras and ω ： c × H → H × c a linear map. We introduce a Horn-ω-smash coproduct （cω H, γ） and give necessary and sufficient conditions for （cω H, γ） to be a Hom-bialgebra. We study the quasi-triangular structures over （cω H, γ） and show the necessary and sufficient conditions for （cω H, γ R） to be a quasi-triangular Hom-Hopf algebra. As applications of our results, we introduce the concept of D（H）＊ and construct quasi-triangular structures over D（H）＊.

关键词： Hom-Hopf algebra Quasi-triangular Hom-Hopf algebra Hom-ω-smash coproduct.

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Evolution of the corrosion Product Film and Its Effect on the Erosion–corrosion Behavior of Two commercial 90cu–10Ni Tubes in Seawater

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Acta Metallurgica Sinica(English Letters) 2018年第11期31卷 1148-1170页

作者： Okpo O. Ekerenam Ai-Li Ma Yu-Gui zheng Si-Yu He Peter c. Okafor cAS Key Laboratory of Nuclear Materials and Safety Assessment Institute of Metal Research Chinese Academyof Sciences Shenyang 110016 China University of chinese Academy of Sciences (UcAS) Beijing 100049 China Department of Pure and Applied chemistry University of Calabar PMB 1115 Calabar CRS Nigeria

The composition and structural evolution of the corrosion product film of two commercial 90cu-10Ni tubes, namely TubeA and Tube B, after being immersed in natural seawater for 1, 3, and 6 months were characterized by scanning electronmicroscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy, and its effecton the erosion--corrosion behavior of the tubes was determined through a rotating cylinder electrode system using variouselectrochemical techniques. For the freshly polished samples used as contrast samples, the flow velocity mainly enhancedthe cathodic reaction at low flow velocities while both the anodic and the cathodic reactions were remarkably accelerated athigher flow velocities. The corrosion product films formed on the two commercial 90cu-10Ni tubes after being immersedin seawater for up to 6 months are of a complex three-layer or multilayer structure. The structural evolution of the films isout of sync for the two tubes. A continuous residual substrate layer depleted of Ni was observed in the inner layer of thefilms on Tube B after 30, 90, and 180 days＇ immersion, while it was observed in the film on Tube A only after 180 days＇immersion. The nature of the inner layer plays a crucial role in the erosion-corrosion resistance of the 90cu-10Ni tubes athigher flow velocity. The film with a compact and continuous inner layer of cu20 doped with Ni2＋ and Ni3＋ which bondsfirmly with the substrate could survive and even get repaired with the increased flow velocity. The film on Tube Bpossessing a hollow and discontinuous inner layer composed of the residual substrate was degraded rapidly with increasingrotation speed in spite of its quite good resistance at the stagnant or lower speed conditions.

关键词： copper-nickel alloy Seawater immersion Erosion-corrosion corrosion product film Flow velocity

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Reliability-based multidisciplinary design optimization using incremental shifting vector strategy and its application in electronic product design

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Acta Mechanica Sinica 2018年第2期34卷 285-302页

作者： Z.L.Huang Y.S.Zhou c.Jiang J.zheng X.Han School of Mechanical and Electrical Engineering Hunan City University State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body College of Mechanical and Vehicle Engineering Hunan University

Use of multidisciplinary analysis in reliabilitybased design optimization(RBDO) results in the emergence of the important method of reliability-based multidisciplinary design optimization(RBMDO). To enhance the efficiency and convergence of the overall solution process,a decoupling algorithm for RBMDO is proposed ***, to decouple the multidisciplinary analysis using the individual disciplinary feasible(IDF) approach, the RBMDO is converted into a conventional form of RBDO. Secondly,the incremental shifting vector(ISV) strategy is adopted to decouple the nested optimization of RBDO into a sequential iteration process composed of design optimization and reliability analysis, thereby improving the efficiency significantly. Finally, the proposed RBMDO method is applied to the design of two actual electronic products: an aerial camera and a car pad. For these two applications, two RBMDO models are created, each containing several finite element models(FEMs) and relatively strong coupling between the involved disciplines. The computational results demonstrate the effectiveness of the proposed method.

关键词： Reliability-based design optimization(RBDO) Multidisciplinary design optimization(MDO) Incremental shifting vector(ISV) Decoupling algorithm Electronic product

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A Better candidate for Dark Matter is cosmic Plasma

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Research in Astronomy and Astrophysics 2023年第10期23卷 277-280页

作者： Yi-Jia zheng National Astronomical Observatories Chinese Academy of SciencesBeijing 100101China

In the ΛcDM cosmological model, based on observations of supernovae Ia, the cosmic dark energy density is assumed to be Ω_(Λ)~ 0.70 and the gravitational mass density is assumed to be Ω_(m)~ 0.30. Based on the assumption that the observed cosmic microwave background(cMB) is a thermal relic of the early hot universe, the cosmic plasma density should be small, i.e., Ω_(b)~ 0.05(otherwise the Sunyaev-Zeldovich effect of the cosmic plasma would ruin the observed cMB's perfect blackbody spectrum). To fill the gap between Ω_(m) and Ω_(b), non-baryonic dark matter Ω_(c)~ 0.25 is introduced into the ΛcDM model. If the cMB is the result of a partial thermal equilibrium between cosmic radiation and cosmic plasma, then the observed perfect blackbody spectrum of the cMB can coexist with cosmic plasma. In this case, it is not necessary to introduce non-baryonic cold dark matter into cosmological models. A better candidate for dark matter is the cosmic plasma.

关键词： cosmology:theory (cosmology:)dark matter gravitational lensing:weak X-rays:galaxies:clusters

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Shipborne radar maneuvering target tracking based on the variable structure adaptive grid interacting multiple model

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Journal of Zhejiang University-Science c(computers and Electronics) 2013年第9期14卷 733-742页

作者： zheng-wei ZHU School of Information Engineering Southwest University of Science and Technology Mianyang 621010 China

The trajectory of a shipbome radar target has a certain complexity, randomness, and diversity. Tracking a strong maneuvering target timely, accurately, and effectively is a key technology for a shipbome radar tracking system. combining a variable structure interacting multiple model with an adaptive grid algorithm, we present a variable structure adaptive grid inter- acting multiple model maneuvering target tracking method. Tracking experiments are performed using the proposed method for five maneuvering targets, including a uniform motion - uniform acceleration motion target, a uniform acceleration motion - uni- form motion target, a serpentine locomotion target, and two variable acceleration motion targets. Experimental results show that the target position, velocity, and acceleration tracking errors for the five typical target trajectories are small. The method has high tracking precision, good stability, and flexible adaptability.

关键词： Shipbome radar Target tracking Variable structure Interacting multiple model Adaptive grid algorithm

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