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A new species of Leptocycas (Zamiaceae) from the Upper Triassic sediments of Liaoning Province,china

Journal of Systematics and Evolution 2010年第4期48卷 286-301页

作者： 1,2,3Jian-Wei ZHANG 2Jian-Xin YAO 1Jia-Rui CHEN 1cheng-Sen LI 1(State Key Laboratory of Systematic and Evolutionary Botany,institute of Botany,chinese academy of sciences,beijing 100093,china) 2(State Key Laboratory of Stratigraphy and Paleontology,institute of Geology,chinese academy of Geological sciences,beijing 100037,china) 3(Graduate University,chinese academy of sciences,beijing 100049,china) (State Key Laboratory of Systematic and Evolutionary Botany Institute of Botany Chinese Academy of Sciences Beijing 100093 China) (State Key Laboratory of Stratigraphy and Paleontology Institute of Geology Chinese Academy of Geological Sciences Beijing 100037 China) (Graduate University Chinese Academy of Sciences Beijing 100049 China)

A new cycad,Leptocycas yangcaogouensis ***.,was found in sediments from the Late Triassic in western Liaoning,*** pinnately compound leaves(Pseudoctenis type)are screwed in a crown on the stem *** leaflets are linear,with parallel veins and decurrent bases on the *** leaf bases are *** cataphylls intermix with the *** female cone is ovoid in *** characteristics of the new plant are more similar to those of Leptocycas gracilis,a Triassic cycad from North America,but the new species differs from *** in the size of its stem(7–8 vs.3–5 cm in diameter,respectively),leaves(length×width 100×16 vs.30×7 cm,respectively)and leaf density along the stem(4–6 vs.1–2 bases/1 cm length,respectively).Both *** and ***,having leaves of the Pseudoctenis type,show a closer relationship to the extant Dioon of *** present study provides evidence for the origin of the genus Dioon,which may have come from Leptocycas plants of the *** would be assumed that the extent cycads in Zamiaceae originate from the pteridosperms in the Late Paleozoic and have evolved through the stage of *** and *** in Late Triassic,and reaching the extant Dioon.

关键词： china Cycadales Leptocycas Upper Triassic Zamiaceae

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Superconductivity at 36 K in gadolinium-arsenide oxides GdO_(1-x)F_xFeAs

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Science china(Physics,Mechanics & Astronomy) 2008年第6期51卷 719-722页

作者： cheng Peng, FANG Lei, YANG huan, Zhu XiYu, MU Gang, LUO huiQian, WANG ZhaoSheng & WEN Haihu National Laboratory for Superconductivity, institute of Physics, chinese academy of sciences, beijing 100190, china beijing National Laboratory for Condensed Matter Physics, institute of Physics, chinese academy of sciences, beijing 100190, china National Laboratory for Superconductivity Institute of Physics Chinese Academy of Sciences Beijing China beijing National Laboratory for Condensed Matter Physics Institute of Physics Chinese Academy of Sciences Beijing China

In this paper we report the fabrication and superconducting properties of GdO1-xFxFeAs. It was found that when x is equal to 0.17, GdO0.83F0.17FeAs is a su-perconductor with the onset transition temperature Tcon ≈ 36.6 K. Resistivity anomaly near 130 K was observed for all samples up to x = 0.17, and such a phenomenon is similar to that of LaO1-xFxFeAs. Hall coefficient indicates that GdO1-xFxFeAs is conducted by electron-like charge carriers.

关键词： iron-based superconductor high-temperature superconductor

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Negative refraction in two-dimensional photonic crystals

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Progress in Natural Science:Materials International 2006年第10期16卷 1027-1032页

作者： REN Xiaobin, REN Kun, FENG Zhifang, FENG Shuai and REN cheng ( School of Physics Science and Information Technology, Liaocheng University, Liaocheng 252059, china beijing National Laboratory for Condensed Matter Physics, institute of Physics, chinese academy of sciences, beijing 100080, china) School of Physics Science and Information Technology Liaocheng University Liaocheng 252059 China beijing National Laboratory for Condensed Matter Physics Institute of Physics Chinese Academy of Sciences Beijing 100080 China

Recent progress made in research on negative refraction in two-dimensional photonic crystals is reviewed. Special attentions are paid to the research results of our group. We explore the underlying mechanism governing the occurrence of negative refraction in periodic and quasiperiodic photonic crystals. These results may be useful references for the application of photonic crystals. The perspectives of future research on negative refraction are briefly predicted.

关键词： negative refraction photonic crystals superlens subwavelength imaging equifreqnency surface.

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Superconductivity in Ti-doped iron-arsenide compound Sr_4Cr_(0.8)Ti_(1.2)O_6Fe_2As_2

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Science china(Physics,Mechanics & Astronomy) 2009年第12期52卷 1876-1878页

作者： Zhu XiYu,HAN Fei,MU Gang,cheng Peng,SHEN Bing,ZENG Bin & WEN Haihu National Laboratory for Superconductivity,institute of Physics,chinese academy of sciences,beijing 100190,china beijing Na-tional Laboratory for Condensed Matter Physics,institute of Physics,chinese academy of sciences,beijing 100190,china National Laboratory for Superconductivity Institute of Physics Chinese Academy of Sciences Beijing China beijing National Laboratory for Condensed Matter Physics Institute of Physics Chinese Academy of Sciences Beijing China

Superconductivity was achieved in Ti-doped iron-arsenide compound Sr4Cr0.8Ti1.2O6Fe2As2 (abbreviated as Cr-FeAs-42622). The X-ray diffraction measurement shows that this material has a layered structure with the space group of P4/nmm,and with the lattice constants a = b = 3.9003  and c = 15.8376 . Clear diamagnetic signals in ac susceptibility data and zero-resistance in resistivity data were detected at about 6 K,confirming the occurrence of bulk superconductivity. Meanwhile we observed a supercon-ducting transition in the resistive data with the onset transition temperature at 29.2 K,which may be induced by the nonuniform distribution of the Cr/Ti content in the FeAs-42622 phase.

关键词： iron-based superconductor high-temperature superconductor Perovskite

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Bifurcation and Chaos in a Weakly Nonlinear System Subjected to Combined Parametric and External Excitation

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Acta Mathematicae Applicatae Sinica 2002年第3期18卷 501-512页

作者： Wei Li, Peng-cheng Xuinstitute of Mathematics, beijing University of Chemical Technology, beijing 100029, chinainstitute of Applied Mathematics, academy of Mathematics and System sciences, chinese academy of sciences, beijing 100080, china institute of Mathematics Beijing University of Chemical Technology Beijing China institute of Applied Mathematics Academy of Mathematics and System Sciences Chinese Academy of Science Beijing China

In this paper the dynamics of a weakly nonlinear system subjected to combined parametric and external excitation are discussed. The existence of transversal homoclinic orbits resulting in chaotic dynamics and bifurcation are established by using the averaging method and Melnikov method. Numerical simulations are also provided to demonstrate the theoretical analysis.

关键词： Bifurcation chaos transversal homoclinic orbit

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Improving the accuracy of image-based forest fire recognition and spatial positioning

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Science china(Technological sciences) 2010年第S1期53卷 184-190页

作者： JIANG LiLi 1,QI QingWen 1,ZHANG An 1,GUO Chaohui 2 & cheng Xi 1,3 1 institute of Geographical sciences and Natural Resources Research,chinese academy of sciences,beijing 100101,china 2 china Center for Resources Satellite Data and Applications,beijing 100094,china 3Graduate University of chinese academy of sciences,beijing 100049,china institute of Geographical sciences and Natural Resources Research Chinese Academy of Sciences Beijing China china Center for Resources Satellite Data and Applications Beijing China Graduate University of chinese academy of sciences Beijing China

Forest fires are frequent natural *** is necessary to explore advanced means to monitor,recognize and locate forest fires so as to establish a scientific system for the early detection,real-time positioning and quick fighting of forest *** paper mainly expounds methods and algorithms for improving accuracy and removing uncertainty in image-based forest fire recognition and spatial ***,we discuss a method of forest fire recognition in visible-light *** are four aspects to improve accuracy and remove uncertainty in fire recognition:(1)eliminating factors of interference such as road and sky with high brightness,red leaves,other colored objects and objects that are lit up at night,(2)excluding imaging for specific periods and azimuth angles for which interference phenomena repeatedly occur,(3)improving the thresholding method for determining the flame border in image processing by adjusting the threshold to the season,weather and region,and (4)integrating the visible-light image method with infrared image ***,we examine infrared-image-based methods and approaches of improving the accuracy of forest fire recognition by combining the spectrum threshold with an object feature value such as the normalized difference vegetation index and excluding factors of disturbance such as interference signals,extreme weather and high-temperature ***,a method of visible analysis to enhance the accuracy of forest fire positioning is examined and realized;the method includes decreasing the visual angle,selecting central points,selecting the largest spots,and judging the selection of fire spots according to the central *** studies are examined and the results are found to be satisfactory.

关键词： forest fire monitoring spatial positioning accuracy improvement

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Phenylalanine deprivation inhibits multiple myeloma progression by perturbing endoplasmic reticulum homeostasis

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Acta Pharmaceutica Sinica B 2024年第8期14卷 3493-3512页

作者： Longhao cheng Xiaoxue Wang Aijun Liu Ying Zhu hu cheng Jiangling Yu Lili Gong Honglin Liu Guolin Shen Lihong Liu institute of Clinical Medical sciences ChinaeJapan Friendship HospitalCapital Medical UniversityBeijing 100029China Department of Pharmacy ChinaeJapan Friendship HospitalBeijing 100029China beijing Chao-Yang Hospital Capital Medical UniversityBeijing 100020China institute of Chemicals Safety Chinese Academy of Inspection and QuarantineBeijing 100020China

Amino acid metabolic remodeling is a hallmark of cancer,driving an increased nutritional demand for amino *** acids are pivotal for energetic regulation,biosynthetic support,and homeostatic maintenance to stimulate cancer ***,the role of phenylalanine in multiple myeloma(MM)remains ***,we demonstrate that phenylalanine levels in MM patients are decreased in plasma but elevated in bone marrow(BM)*** the treatment,phenylalanine levels increase in plasma and decrease in *** suggests that changes in phenylalanine have diagnostic value and that phenylalanine in the BM microenvironment is an essential source of nutrients for MM *** requirement for phenylalanine by MM cells exhibits a similar *** phenylalanine utilization suppresses MM cell growth and provides a synergistic effect with Bortezomib(BTZ)treatment in vitro and murine ***,phenylalanine deprivation induces excessive endoplasmic reticulum stress and leads to MM cell apoptosis through the ATF3eCHOPeDR5 *** with ATF3 significantly affects phenylalanine deprivation *** conclusion,we have identified phenylalanine metabolism as a characteristic feature of MM metabolic *** is necessary for MM proliferation,and its aberrant demand highlights the importance of lowphenylalanine diets as an adjuvant treatment for MM.

关键词： Multiple myeloma Phenylalanine Amino acid metabolism Nutrient deprivation Cancer therapy Endoplasmic reticulum stress ATF3 Apoptosis

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Exploration of combined adjustment laws about IGV,stator and rotational speed in off-design conditions in an axial compressor

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中国科学：技术科学英文版 2010年第4期53卷 969-975页

作者： hu YanMing1,2 & NIE ChaoQun1 1 Key Laboratory of Advanced Energy and Power Technology,institute of Engineeting Thermophysics,chinese academy of Science,beijing 100190,china 2 Graduate School of chinese academy of sciences,beijing 100190,china Key Laboratory of Advanced Energy and Power Technology Institute of Engineeting Thermophysics Chinese Academy of Science Beijing China Graduate School of chinese academy of sciences Beijing China

Experimental investigations are performed in a three-stage low-speed axial compressor with variable inlet guide vanes(IGV) and adjustable *** characteristics of the compressor,especially the efficiency and stall margin,are analyzed in design and off-design operation conditions by adjusting stagger angles of IGV and stators as well as changing the rotational *** experimental results show that the off-design performance of the multistage axial compressor is improved by restaggering of IGV and stators related to rotational *** the background of engineering applications,digital signal processing(DSP) technique is used to realize online adjustment of stagger angles according to the corresponding relations between incidence angles of rotor and rotational speed.

关键词： axial compressor IGV surge DSP techniques off-design

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Numerical study on onset of oscillatory thermocapillary flow in rectangular liquid pool

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Science china(Technological sciences) 2010年第4期53卷 1069-1076页

作者： hu WenRui,TANG ZeMei & LI Kai Key Laboratory of Microgravity(National Microgravity Laboratory),institute of Mechanics,chinese academy of sciences,beijing10090,china Key Laboratory of Microgravity (National Microgravity Laboratory) Institute of Mechanics Chinese Academy of Sciences Beijing China

Thermocapillary flow in a rectangular liquid pool of large Prandtl fluid(Pr=105.6) is numerically studied in *** thermocapillary flow arises when the imposed temperature difference between the sidewalls exceeds a critical *** fluctuations of the oscillatory flow,accompanied by the propagation of the hydrothermal wave from the cold sidewall to the hot one,are much smaller than the time-averaged velocity and temperature *** corresponding disturbance cells arise in the centre of the liquid pool initially,and extend to the whole region with the increasing imposed temperature *** present study reveals the different characteristics of the oscillatory themocapillary flow in the rectangular liquid pool as compared to the cases in other configurations.

关键词： hydrothermal wave bifurcation numerical simulation microgravity

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Initiation and Development of Water Film by Seepage

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Journal of Mountain Science 2010年第4期7卷 361-366页

作者： LU Xiaobing CUI Peng hu Kaiheng ZHANG Xuhui institute of Mechanics Chinese Academy of Sciences Beijing 100080 China institute of Mountain Hazards & Environment Chinese Academy of Sciences Chengdu 610041 China

When water seeps upwards through a saturated soil layer,the soil layer may become instability and water films occur and *** film serves as a natural sliding surface because of its very small ***,debris flow may *** investigate this phenomenon,a pseudothree-phase media is presented *** discontinuity method is used to analyze the expansion velocity of water ***,perturbation method is used to analyze the case that a water flow is forced to seep upwards through the soil layer while the movement of the skeleton may be neglected relative to that of *** theoretical evolutions of pore pressure gradient,effective stress,water velocity,the porosity and the eroded fine grains are *** can be seen clearly that with the erosion and redeposited of fine grains,permeability at some positions in the soil layer becomes smaller and smaller and,the pore pressure gradient becomes bigger and bigger,while the effective stress becomes smaller and *** the effective stress equals zero,***,the water film *** is shown also that once a water film occurs,it will be expanded in a speed of U(t)(1-ε).

关键词： Slope Seepage Debris flow Water film

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