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Chemical Research in Chinese Universities 2024年第1期40卷 55-63页

作者： WANG Tingting WANG Jia xi Yongjie HU Bin LI Fuwei state Key laboratory for Oxo Synthesis and Selective Oxidation Lanzhou Institute of Chemical PhysicsChinese Academy of SciencesLanzhou 730000P.R.China university of Chinese Academy of Sciences Beijing 100049P.R.China

Selective activation of C-O bond is of fundamental importance in the precise conversion of oxygenates into value-added compounds in an atom-economic and sustainable manner, and meanwhile, the structurally well-defined dual-atoms catalysts (DACs) have been scarcely investigated in this field. In this study, a series of transition metal DACs anchored on nitrogen-doped graphene (TM2/NC, TM=Pt, Ir, Rh, Pd, Ru, Co, Ni and Cu) was constructed to make a comprehensive investigation of their selectivity in the hydrogenative transformation of furfuryl alcohol (FAL), an important biomass platform molecule, to 1,2-pentanediol (1,2-PeD) via selective cleavage of furanic C5-O bond, by density functional theory (DFT) calculations and microkinetic modeling. We found that Ir2/NC demonstrated a high selectivity for the cleavage of furanic C5-O bond to produce 1,2-PeD, while the production of THFAL or 1,5-pentanediol (1,5-PeD) on other TM2/NC catalysts are more favorable. Furthermore, we found that the selective C-O bond cleavage of FAL furan ring is affected by the orbital overlap between the d-orbitals of the anchored metal atoms and the p-orbitals of the adsorbed C atom in FAL, suggesting that the selectivity of the C-O bond cleavage is inextricably related with the electronic property of the anchored metals.

关键词： Furfuryl alcohol Hydrogenation Dual-atom catalyst Density functional theory(DFT)calculation

Anatomical variations of living and fossil Liquidambar leaves:A proxy for paleoenvironmental reconstruction

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Science china Earth Sciences 2011年第4期54卷 493-508页

作者： xiAO Liang 1,2,3.4,SUN BaiNian 1,2,,LI xiangChuan 1,REN Wenxiu 1 &JIA Hui 1 1 Key laboratory of Western china's Environmental Systems of the Ministry of Education and College of Earth and Environment Science,Lanzhou university,Lanzhou 73.000,{3. 2 state Key laboratory of Palaeobiology and Stratigraphy,Nanjing Institute of geology and Palaeontology,Chinese Academy of Sciences,Nanjing 210008,{3. 3.College of Arts and Sciences,Bryant university,Smithfield RI 02917,U.S.A. 4 Key laboratory of Western china's Mineral Resources and Geological Engineering of Ministry of Education,Chang’an university,xi’an 710054,{3. 1. Key laboratory of Western china’s Environmental Systems of the Ministry of Education and College of Earth and Environment Science Lanzhou University Lanzhou 730000 China2. State Key Laboratory of Palaeobiology and Stratigraphy Nanjing Institute of Geology and Palaeontology Chinese Academy of Sciences Nanjing 210008 China3. College of Arts and Sciences Bryant University Smithfield RI 02917 USA4. Key Laboratory of Western China’s Mineral Resources and Geological Engineering of Ministry of Education Chang’an University Xi’an 710054 China

Based on living ***,we have established that such epidermal cell properties as epidermal cell circumference(Circum.) ,undulation index(UI) ,epidermal cell area(EA) on both upper and lower epidermis and the corresponding epidermal cell density(ED) ,are suitable to differentiate between sun and shade ***,stomatal properties on the lower epidermis,including stomatal length(SL) ,stomatal pore length(PL) and the corresponding stomatal density(SD) ,are reliable parameters to identify sun/shade *** this anatomical approach was applied to 18 leaf remains of *** from the Miocene xiannanshan Formation,Zhejiang Province(eastern china) ,and the fossil leaves were sorted into two groups,namely,sun and shade *** indicates that anatomical differences between sun and shade leaves found in living species could be used for fossil ***,the variation of UI between sun and shade morphotypes is larger on the upper epidermis as compared with the lower epidermis,showing that the UI on the upper epidermis is more sensitive to environmental *** addition,anatomical features are more variable in sun leaves than in shade leaves for both modern and fossil Liquidambar,suggesting sun leaves may be more sensitive to environmental *** leaves can then be a better indicator of paleoenvironmental ***,stomatal parameters of sun morphotype should be adopted on reconstructing paleoenvironments using Liquidambar leaf *** the other hand,the three-lobed fossil *** leaf assemblage in the xiananshan Formation is represented by an almost similar percentage of sun and shade morphotypes(56%and 44%,respectively) ,which is attributed to the short transport before *** a result,identifying sun/shade morphotypes are very useful in reconstructing paleoenvironments based on fossil leaves of Liquidambar.

关键词： Liquidambar formosana Liquidambar miosinica leaf anatomy the Miocene xiananshan Formation sun and shade leaves

Optimal user scheduling and power control in multi-user cognitive broadcast systems

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Science china(Information Sciences) 2012年第6期55卷 1402-1414页

作者： WANG QunHuan 1,2,3.WANG HuiMing 1,2,3.& YIN QinYe 1,3.1 School of Electronic and Information Engineering,xi'an Jiaotong university,xi'an 710049,china 2 state Key Lab for Integrated Services Networks,xidian university,xi'an 710071,china 3.Ministry of Education Key Lab for Intelligent Networks and Network Security,xi'an Jiaotong university,xi'an 710071,china. 1. School of Electronic and Information Engineering Xi’an Jiaotong University Xi’an 710049 China2. State Key Lab for Integrated Services Networks Xidian University Xi’an 710071 China3. Ministry of Education Key Lab for Intelligent Networks and Network Security Xi’an Jiaotong University Xi’an 710071 China

Cognitive radio systems should not only have the ability to sense and exploit "frequency spectrum holes",but also the ability to sense and utilize "spatial spectrum holes".In this paper,we consider the issue of maximizing the throughput of the cognitive systems by fully utilizing "spatial spectrum holes" brought in by multiple cognitive users,in the scenario where a pair of licensed users and a cognitive broadcast system share multiple spectrum *** exploiting the channel reciprocity under the premise that the licensed system adopts the time-division-duplexing (TDD) mode,we propose a more practical cognitive access scheme that can sense the interference at the licensed user caused by the cognitive transmitter,based on the existing feedback signals from the licensed user to the licensed base *** both interferences from the licensed base station to the cognitive receiver and from the cognitive transmitter to the licensed user into consideration,we investigate the optimal user scheduling and power allocation scheme that can maximize the ergodic sum rate of the cognitive *** show that scheduling the user whose channel gain to interference and noise ratio (CGINR) is the largest for each frequency band is *** also derive the dynamic power allocation scheme meeting the three practical constraints,i.e.,the transmitter's average transmission power constraint,the power amplifier's instantaneous transmission power constraint,and the interference power constraint at the licensed *** result shows that in different coherent time intervals and different frequency bands,the power allocation has a multi-level waterfilling *** analysis shows that the strategy scheduling user with the largest CGINR introduces significant performance improvement compared with the traditional strategy scheduling user with the largest channel gain to noise ratio (CGNR).We also illustrate the impact of power constraints and the number of users on system p

关键词： cognitive radio distributed spatial spectrum holes opportunistic scheduling power allocation

Lithosphere types in North china:Evidence from geology and geophysics

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Science china Earth Sciences 2005年第11期48卷 1809-1827页

作者： QIU Ruizhao1,2, DENG Jinfu3. ZHOU Su3. LI Jinfa4, xiAO Qinghui1,5, WU Zongxu6 & LIU Cui3.1. Institute of geology, Chinese Academy of Geological Sciences, Beijing 10003., china 2. Development and Research Center, china Geological Survey, Beijing 10003., china 3. china university of Geosciences, Beijing 100083. china 4. china university of Geosciences, Wuhan 43.074, china 5. Information Center of Ministry of Land and Resources, Beijing 100812, china 6. Institute of geology, state Seismological Bureau, Beijing 100029, china 1. Institute of geology Chinese Academy of Geological Sciences 100037 Beijing China 2. Development and Research Center China Geological Survey 100037 Beijing China 3. china university of Geosciences 100083 Beijing China 4. china university of Geosciences 430074 Wuhan China 5. Information Center of Ministry of Land and Resources 100812 Beijing China 6. Institute of geology State Seismological Bureau 100029 Beijing China

On the basis of the characteristics of geology and geophysics in North china, three types of lithosphere, namely, the cratonic, the orogenic and the rift lithospheres can be classified. In terms of petrological method (based on the information from Precambrian rock assemblages, igneous activities, deep-seated enclaves, etc.) and the relationship between seismic velocity and rock compositions, the crust-mantle petrological and chemical structure models can be set up. Researching results indicate that the geology and geophysics of North china platform bears the similar characteristics in comparison with those of the global typical cratons. The Eerduosi(Ordos) block located in the west of the North china Platform is a remnant of cratonic lithosphere after the North china platform had undergone “activation” in Mesozoic and “reconstruction” in Cenozoic times. The continental crust consists mainly of TTG rock assemblage while the subcontinental lithosphere mantle mainly consists of strongly depleted harzburgite. The craton was finally formed in late Archaean and early Proterozoic, and has been kept in stability up to present; its crustal-mantle petrological structures of lithosphere can be set up as a reference for the study of North china craton and even Sino-Korean craton. In the Mesozoic period, the middle and east areas of North china platform were activated in the Yanshanian orogenic process, the continental crust was reformed by material and heat-transfer of convective mantle and the original crustal TTG component was reconstructed to be granitic crust, and the subcontinental lithosphere man- tle was replaced by the Yanshanian harzburgite-lherzolite. The Yanshan-Taihang Mountains were the remnants of orogenic lithosphere after the rifting in eastern North china in Cenozoic. The present thickness of continental crust and lithosphere in the Yanshan-Taihang Mountains is not equal to their thickness during the Yanshanian orogenic movement because they had undergone the

关键词： lithospheric types,evidence of geology and geophysics,crust-mantle petrological structure,deep process

Effect of Solidification Condition on Microstructure and Mechanical Properties of Single Crystal Superalloy

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Journal of Materials Science & Technology 2001年第1期17卷 89-90页

作者： Wanming ZHANG Wei DU and Hengzhi FU state Key laboratory of Solidification Processing, northwestern Polytechnical {3., xi’an 710072, china northwestern Polytech Univ State Key Lab Solidificat Proc Xian 710072 Peoples R China

CMSX-2 single crystals with different primary dendrite arm spacing were obtained on directional solidification apparatus with high temperature gradient (250 K/cm). The microstructure and elevated temperature stress r... 详细信息

关键词： Single Crystal Superalloy single crystals directional solidification temperature gradient elevated temperature dendrite arm spacing stress rupture

Novel strengthening methods for ultralightweight sandwich structures with periodic lattice cores

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Science china(Technological Sciences) 2010年第3期53卷 875-877页

作者： LU TianJian 1 &ZHANG QianCheng 2 1 MOE Key laboratory for Strength and Vibration,School of Aerospace,xi’an Jiaotong university,xi’an 710049,china 2 {3. Key laboratory for Mechanical Behavior of Materials,School of Material Science and Engineering,xi’an Jiaotong university,xi’an 710049,china 1. MOE Key laboratory for Strength and Vibration School of Aerospace Xi’an Jiaotong University Xi’an 710049 China2. State Key Laboratory for Mechanical Behavior of Materials School of Material Science and Engineering Xi’an Jiaotong University Xi’an 710049 China

Recent development of ultralightweight lattice-cored sandwiches is reviewed,with focus placed on various novel fabrication methods introduced to strengthen these structures,covering not only research results published... 详细信息

关键词： cellular metals strengthening method fabrication sandwich panels

THERMOMECHANICAL RESPONSE OF SMA FIBER COMPOSITES WITH NON-UNIFORM TEMPERATURE DISTRIBUTION

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Acta Mechanica Solida Sinica 2003年第4期16卷 334-344页

作者： Zhang Zhen Wang Jian Shen Yapeng (The state Key laboratory of Mechanical Structural and Vibration,xi’an Jiaotong university,xi’an 710049,{3.) The state Key laboratory of Mechanical Structural and Vibration Xi\'an Jiaotong University Xi\'an 710049 China

A micromechanics method based on the High-Order-Theory developed by Aboudi et *** used to predict the thermomechanical response of composites reinforced by shape memory alloy (SMA) fibers,and the non-uniform thermal distribution in composite arising from the process of heating or cooling is *** numerical development based on this model was coded to predict the thermomechanical response of shape memory alloy fiber/elastomer matrix composite subjected to thermal cycle *** the composite is heated,two heating ways,thermal gradients and heat source by passing an electric current through the SMA fibers are imposed on the composite *** cooling,the first thermal boundary condition and the second thermal boundary condition are subjected to the composite respectively.A series of stress distributions and temperature distributions for different instants are calculated to reveal the interaction between the SMA material and *** is useful to analyze and design the SMA actuator driven by heat source or the surface temperature.

关键词： shape memory alloy composites fiber

DISLOCATION ARRAY AT VARIOUS DEFORMING AND HARDENING STAGES OF STEEL 103.

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Acta Metallurgica Sinica(English Letters) 1995年第3期8卷 195-198页

作者： LUO Jingxi TAN Yuxu (state Key laboratory for Mechanical Behaviour of Materials,xi’an Jiaotong. university,{3. xi'an Jiaotong Univ Xi'an China

The alteration of dislocation arrays in the process of strain hardening for normalized carbon steel 103. was investigated by transmission electron microscopy. At primary stage the separated dislocation lines tend to form tangles and networks, dislocation cells appear at the secondary stage, the amount of the cells increases significantly, its average dimension does not change and the cell walls become clear. The third stage of strain hardening was observed in the process from necking to fracture and shows a straight line segment on the lg σ -lg ε curve, at this time the dislocation cells become smaller and tend to form band structure.

关键词： strain hardening dislocation array cell structure steel 103.

A comparative study on mechanical and vibroacoustic performance of sandwich cylindrical shells with positive,negative,and zero Poisson’s ratio cellular cores

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Journal of Ocean Engineering and Science 2024年第4期9卷 379-390页

作者： Qing Li Peichang Li Yongjin Guo xi’an Liu state Key laboratory of Ocean Engineering Shanghai Jiao Tong UniversityShanghai200240China china Ship Development and Design Center Wuhan430064China MOE Key laboratory of Marine Intelligent Equipment and System Shanghai Jiao Tong UniversityShanghai200240China

Deep-sea submersibles are significant mobile platforms requiring multi-functional capabilities that are strongly determined by the constituent *** cylindrical protective cover can be advanced by designing their sandwiched cellular materials whose physical properties can be readily parameterized and flexibly *** honeycomb materials are capable of possessing tuned positive,negative,or zero Poisson’s ratios(PPR,NPR,and ZPR),which is expected to produce distinct physical performance when utilized as a cellular core of cylindrical shells for the deep-sea submersibles.A novel cylindrical meta-structure sandwiched with the semi-re-entrant ZPR metamaterial has been designed as well as its similarly-shaped sandwich cylindrical shell structures with PPR and NPR *** mechanical and vibroacoustic performance of sandwich cylindrical shells with cellular materials featuring a full characteristic range of Poisson’s ratios are then compared systematically to explore their potential for engineering applications on submerged pressure-resistant *** respective unit cells are designed to feature an equivalent load-bearing *** properties of pressure resistance,buckling,and sound insulation are simulated,respectively,and the orders of each property are then generalized by systematic *** results indicate that the PPR honeycomb core takes advantage of higher structural strength and stability while the ZPR one yields better energy absorption and sound insulation *** NPR one yields moderate properties and has the potential for lower circumferential *** work explores the application of cellular materials with varied Poisson’s ratios and provides guidance for the multi-functional design of sandwich cylindrical meta-structures.

关键词： Sandwich cylindrical shells Poisson’s ratio Pressure-resistant Buckling Vibroacoustic

Multiary turbo code fitting for unitary space-time modulation and its MAP decoding algorithm

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Science china(Information Sciences) 2010年第12期53卷 2610-2619页

作者： ZHANG DaPeng 1,2,3.LU Ju 1,XU HongJi 1 & ZHANG xingYu 1 1 School of Information Science and Engineering,Shandong university,Jinan 250100,china 2 state Key {3. of Integrated Services Networks,xidian university,xi'an 710077,china 3.department of Avionics Engineering,First Aeronautical College of the Air Force,xinyang 464000,china 1. School of Information Science and Engineering Shandong University Jinan 250100 China2. State Key Laboratory of Integrated Services Networks Xidian University Xi’an 710077 China3. Department of Avionics Engineering First Aeronautical College of the Air Force Xinyang 464000 China

Unitary space-time modulation(USTM) fits for rapid Rayleigh flat fading channels as it can realize wireless communication when neither the transmitter nor the receiver knows the channel state information(CSI).However,an intrinsic problem is that only when the signal-to-noise ratio(SNR) is high can it give an ideal bit error rate(BER) *** existing bit-wise processing scheme of the combination of turbo code and USTM improves the BER performance and results in an unacceptable calculation complexity,storage and time delay *** this paper,we propose a multiary processing scheme and its corresponding multiary MAP decoding *** results verify that our scheme can reduce the system complexity while keep a good BER ***,we present the first analysis of the reason for the BER performance deterioration of the combination scheme at low SNR with the help of the definition of USTM.

关键词： multiple-input multiple-output unitary space-time modulation turbo code MAP decoding diversity