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Lithological and Si–O–S isotope geochemistry:constraints on the origin and genetic environment of the selenium(Se)-rich siliceous rocks in Enshi,Hubei Province,China

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Acta Geochimica 2021年第1期40卷 89-105页

作者： Caixia feng Shen Liu Ian M.Coulson State Key Laboratory of Continental Dynamics and Department of Geology Northwest UniversityXi'an 710069China Solid Earth Studies Laboratory Department of GeologyUniversity of ReginaReginaSK S4S 0A2Canada

Se-rich black rock series of the Middle and Late Permian system is widely distributed in Enshi Prefecture with an exposed area of 850 km~2,among which the unique Yutangba black rock series independent selenium deposit with industrial mining significance in the world is ***,the source and metallogenic mechanisms of Se are still *** general,terrestrial weathering and submarine hydrothermal processes are the main source end members of Si and Se,and the related siliceous rocks record the deposition process of Si and Se from different *** study of lithofacies and paleogeography shows that western Hubei belongs to the near eastwest turn of the Yangzi platform in the Middle and Late Permian and becomes an inter-platform basin with nearly north-south ***,the comparative study of the Yutangba deposit and the selenium-rich black rock series in the northern Shadi with high selenium content is expected to reveal the provenance evolution of the two sections in space,and further restrict the Se mineralization mechanism in the Enshi *** the element geochemistry study,the black rock series in two study areas may have formed in a transitional position of either the continental margin or continental slope,in the process of sedimentary,more terrigenous clastic materials *** are rich in lithophile elements V and Cr.δU>1.0,U/Th and V/(V+Ni)ratio indicate that the Se-rich strata of black rock series in the Enshi areas occurred in an anoxic reducing environment and formed in an environment between the ocean basin and the continental *** Si-O isotope geochemistry,the original Si source of the study area is thought to relate to a volcanic eruption,which leads to the enrichment of Si in the *** determined values of S isotope in the black rock series of the two study areas both show the characteristics related to organic reduction/biogenic.

关键词： Se-rich siliceous rocks Geochemistry Si–O–S isotope Origin Sedimentary environment

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Synthesis, Separation and Assignment of Four Geometric mer-Isomers of [Co(2,3-tri)(cmen)Cl]^(2+) System

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Chinese Journal of Structural Chemistry 2004年第1期23卷 44-52页

作者： ZHANGJian-Xin MAOMing-Yi XUESai-feng ZHUQian-Jiang TAOZhu KeyLaboratoryofChemistryforNaturalProductsofGuizhouProvince Guiyang550002China InstituteofAppliedChemistry GuizhouUniversityGuiyang550025China InstituteofAppliedChemistry GuizhouUniversityGuiyang550025ChinaE-mail：gzutao@***

Four geometric mer-isomers in the [Co(2,3-tri)(cmen)Cl]2+ system have been synthesized and well separated (2,3-tri = N-(3-aminoethyl)-1,3-propanediamine; cmen = 1,2-di- aminopropane). Their structures in DMSO-d6 solut... 详细信息

关键词： mer-isomers structure assignment 2D NMR

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Preparation and anti atomic oxygen erosion properties of OPPOSS/PI composites

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International Journal of Minerals,Metallurgy and Materials 2013年第10期20卷 994-1000页

作者： Wei-ping Li Hui-cong Liu Li-li feng School of Materials Science and Engineering Beihang University Key Laboratory of Urban Stormwater System and Water Environment (Ministry of Education) Beijing University of CivilEngineering and Architecture

Atomic oxygen （AO） found in low earth orbit can cause serious erosion to polyimide （PI） materials, which greatly limits their lifetime. 8-phenyl silsesquioxane （OPPOSS） was synthesized, and OPPOSS/PI composites were pre- pared by physical blending, followed by thermal imidization to enhance the AO erosion resistance of PI materials. The morphology, composition, and structure of the composites were analyzed before and after AO exposure in a ground sim- ulated facility of atomic oxygen. After 16 h AO exposure, the OPPOSS/PI composite with 5wt% OPPOSS addition shows an erosion rate of about 1.4×10-24 cm3/atom with only 48% mass loss of that of PI without OPPOSS addition. The mixture of OPPOSS nano molecules is assembled into a kind of regular square structure and distributed evenly in OPPOSS/PI composites. Some SiO2 particles are formed in the composites during AO exposure, which can act as ＂inert points＂ to reduce the AO erosion rate of OPPOSS/PI composites.

关键词： composite materials polyimides silsesquioxanes atomic oxygen erosion

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Derivation of a second-order model for Reynolds stress using renormalization group analysis and the two-scale expansion technique

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Acta Mechanica Sinica 2011年第5期27卷 649-659页

作者： Xiao-Hong Wang Zheng-feng Liu Xiao-Xia Lu Department of Thermal Science and Energy Engineering University of Science and Technology of China230026 Hefei China

With the two-scale expansion technique proposed by Yoshizawa,the turbulent fluctuating field is expanded around the isotropic *** a low-order two-scale expansion,applying the mode coupling approximation in the Yakhot-Orszag renormalization group method to analyze the fluctuating field,the Reynolds-average terms in the Reynolds stress transport equation,such as the convective term,the pressure-gradient-velocity correlation term and the dissipation term,are *** numerical examples：turbulent flow past a backward-facing step and the fully developed flow in a rotating channel,are presented for testing the efficiency of the proposed second-order *** these two numerical examples,the proposed model performs as well as the Gibson-Launder （GL） model,giving better prediction than the standard k-ε model,especially in the abilities to calculate the secondary flow in the backward-facing step flow and to capture the asymmetric turbulent structure caused by frame rotation.

关键词： Turbulent modeling Renormalization group Two-scale expansion Reynolds stress transport equation Second-order model

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On Blocks in Restricted Representations of Lie Superalgebras of Cartan Type

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Acta Mathematica Sinica,English Series 2020年第9期36卷 1061-1075页

作者： Fei Fei DUAN Bin SHU Yu feng YAO School of Mathematical Sciences Hebei Normal UniversityShijiazhuang 050024P.R.China School of Mathematical Sciences East China Normal UniversityShanghai 200241P.R.China Department of Mathematics Shanghai Maritime UniversityShanghai 201306P.R.China

Let g be a restricted Lie superalgebra of Cartan type W(n),S(n)or H(n)over an alge-braically closed field k of prime characteristic p>3,in the sense of modular version of Kac's definition in *** this note,we show that the restricted representation category over g has only one block(reckoning parities in).This phenomenon is very diff erent from the case of characteristic zero.

关键词： Lie superalgebra of Cartan type restricted representation block

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Autophagy: novel insights into therapeutic target of electroacupuncture against cerebral ischemia/reperfusion injury

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Neural Regeneration Research 2019年第6期14卷 954-961页

作者： Ya-Guang Huang Wei Tao Song-Bai Yang Jin-feng Wang Zhi-Gang Mei Zhi-Tao feng Medical College of China Three Gorges University Yichang Hospital of Traditional Chinese Medicine Clinical Medical College of Traditional Chinese MedicineChina Three Gorges University

Electroacupuncture is known as an effective adjuvant therapy in ischemic cerebrovascular disease. However, its underlying mechanisms remain unclear. Studies suggest that autophagy, which is essential for cell survival and cell death, is involved in cerebral ischemia reperfusion injury and might be modulate by electroacupuncture therapy in key ways. This paper aims to provide novel insights into a therapeutic target of electroacupuncture against cerebral ischemia/reperfusion injury from the perspective of autophagy. Here we review recent studies on electroacupuncture regulation of autophagy-related markers such as UNC-51-like kinase-1 complex, Beclin1, microtubule-associated protein-1 light chain 3, p62, and autophagosomes for treating cerebral ischemia/reperfusion injury. The results of these studies show that electroacupuncture may affect the initiation of autophagy, vesicle nucleation, expansion and maturation of autophagosomes, as well as fusion and degradation of autophagolysosomes. Moreover, studies indicate that electroacupuncture probably modulates autophagy by activating the mammalian target of the rapamycin signaling *** review thus indicates that autophagy is a therapeutic target of electroacupuncture treatment against ischemic cerebrovascular diseases.

关键词： nerve regeneration autophagy electroacupuncture cerebral ischemia/reperfusion injury mTOR LC3 Beclin1 p62 neuroprotection neural regeneration

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Deep Learning-Based Symbol Detection for Time-Varying Nonstationary Channels

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China Communications 2022年第3期19卷 158-171页

作者： Xuantao Lyu Wei feng Ning Ge Xianbin Wang Research Center of Networks and Communications Peng Cheng LaboratoryShenzhen 518055China Department of Electronic Engineering Tsinghua UniversityBeijing 100084China Department of Electrical and Computer Engineering The University of Western OntarioLondonON N6A 5B9Canada

The highly dynamic channel(HDC)in an extremely dynamic environment mainly has fast timevarying nonstationary *** this article,we focus on the most difficult HDC case,where the channel coherence time is less than the symbol *** this end,we propose a symbol detector based on a long short-term memory(LSTM)neural *** the sampling sequence of each received symbol as the LSTM unit's input data has the advantage of making full use of received information to obtain better *** addition,using the basic expansion model(BEM)as the preprocessing unit significantly reduces the number of neural network ***,the simulation part uses the highly dynamic plasma sheath channel(HDPSC)data measured from shock tube *** results show that the proposed BEM-LSTM-based detector has better performance and does not require channel estimation or channel model information.

关键词： highly dynamic channel deep neural network long short-term memory basis expansion model symbol detection

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A method for classifying orbits near asteroids

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Acta Mechanica Sinica 2014年第3期30卷 316-325页

作者： Xian-Yu Wang Sheng-Ping Gong Jun-feng Li Department of Aerospace Engineering Tsinghua University

A method for classifying orbits near asteroids under a polyhedral gravitational field is presented, and may serve as a valuable reference for spacecraft orbit design for asteroid exploration. The orbital dynamics near aster- oids are very complex. According to the variation in orbit characteristics after being affected by gravitational perturbation during the periapsis passage, orbits near an as- teroid can be classified into 9 categories：（1） surrounding- to-surrounding, （2） surrounding-to-surface, （3） surrounding- to-infinity, （4） infinity-to-infinity, （5） infinity-to-surface, （6） infinity-to-surrounding, （7） surface-to-surface, （8） surface- to-surrounding, and （9） surface-to- infinity. Assume that the orbital elements are constant near the periapsis, the gravitation potential is expanded into a harmonic series. Then, the influence of the gravitational perturbation on the orbit is studied analytically. The styles of orbits are dependent on the argument of periapsis, the periapsis radius, and the periapsis velocity. Given the argument of periapsis, the orbital energy before and after perturbation can be derived according to the periapsis radius and the periapsis velocity. Simulations have been performed for orbits in the gravitational field of 216 Kleopatra. The numerical results are well consistent with analytic predictions.

关键词： Asteroid. Orbital classification 216 Kleopatra-Orbit prediction Polyhedral gravitational field

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ANTI-BIOFOULING BY DEGRADATION OF POLYMERS

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Chinese Journal of Polymer Science 2012年第3期30卷 337-342页

作者： Chun-feng Ma Hong-jun Yang 张广照 Faculty of Materials Science and Engineering South China University of TechnologyGuangzhou 510640Chin Hefei National Laboratory for Physical Sciences at Microscale Department of Chemical PhysicsUniversity of Science and Technology of ChinaHefei 230026China

Copolymers of methyl methacrylate （MMA） and acrylate terminated poly（ethylene oxide-co-ethylene carbonate）（PEOC） macromonomer （PEOCA） were synthesized, and the degradation of the polymers was investigated by use of quartz crystal microbalance with dissipation （QCM-D）. It is shown that the polymeric surface exhibits degradation in seawater depending on the content of the side chains. Field tests in seawater show that the surface constructed by the copolymer can effectively inhibit marine biofouling because it can be self-renewed due to degradation of the copolymer.

关键词： Anti-biofouling Degradation Poly(ethylene carbonate) Poly(ethylene oxide).

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Evaluation of the performance of surface treatments on concrete durability

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2010年第5期11卷 349-355页

作者： Yu-xi ZHAO Pan-feng DU Wei-liang JIN Institute of Structural Engineering Zhejiang University Hangzhou 310027 China

This paper reports on a laboratory-based study carried out to evaluate the effectiveness of surface treatments on the durability of concrete and suggests a number of different evaluation methodologies for assessing the performance of various surface treatments. Durability of untreated and treated concrete specimens was evaluated by measuring chloride diffusion,charge passing capacity,air permeability and water absorption. A total of six concrete surface treatments were selected to represent different generic types,including coating,penetrant and mixed-use treatments. Results show that the concrete specimens with a coating procedure have a better long-term performance and effectiveness than the specimens with the penetrant treatments. This work also indicates that the wetting and drying cycles test can be used to assess the weatherability of the surface treatments. The ASTM C 1202 and the Autoclam air permeability test can be used to evaluate the effectiveness of surface treatments quantitatively. Further work is needed,however,to assess the longevity of the various surface treatments.

关键词： Surface treatment Concrete Durability Evaluation

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