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Microstructure Development of Directionally Solidified Nb-Ti-Si Based Ultrahigh Temperature Alloy

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稀有金属材料与工程 2009年第A3期38卷 24-27页

作者： guo Haisheng guo Xiping yao Chengfang State Key Laboratory of Solidification Processing Northwestern Polytechnical University Xi＇an 710072 China

Integrally directional solidification of an Nb-Ti-Si based ultrahigh temperature alloy was performed in an ultrahigh temperature and high thermal gradient furnace with the use of ceramic crucibles. The microstructural evolution with the withdrawing rate increasing during directional solidification was revealed. The integrally directionally solidified microstructure was composed of couple grown lamellar (Nbss+(Nb,X)5Si3) eutectic colonies and a few hexagonally cross-sectioned (Nb,X)5Si3 columns (X represents Ti and Hf elements). All the directionally solidified microstructure was straightly aligned along the longitudinal axis of the specimens. With increasing of the withdrawing rate, the average diameter of the eutectic cells and inter lamella spacings in the eutectic cell decreased. The near-planar solid/liquid interface appeared when the withdrawing rate was 1μm/s, and the cellular solid/liquid interface formed when the withdrawing rate was 5 μm/s.

关键词：超高温合金物理性能热梯度定向凝固组织

Synthesis and properties of novel thermotropic liquid crystalline copoly(ester-imide)s

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Chinese Chemical Letters 2009年第12期20卷 1510-1513页

作者： guo yao Yi Gu State Key Laboratory of Polymer Materials Engineering of China College of Polymer Science and Engineering Sichuan University Chengdu 610065 China

Four novel copoly（ester-imide）s based on 3,3′,4,4′-biphenyltetracarboxylic dianhydride, bis（trimellitic acid anhydride） phenyl ester and di-p-aminophenyl ester of dicarboxylic acids were synthesized via two-step method in order to investigate whether two imide mesogenic units with different conformation and polarity could control the formation of LC-phase. Polarizes light microscopy （PLM） and differential scanning calorimetry （DSC） have shown that three polymers formed the nematic phase with ＂thread schlieren texture＂ and a polymer formed the nematic phase with ＂Inversion walls texture＂.

关键词： Copoly(ester-imide) Inversion walls texture Mesogenic unit Thermotropic liquid crystalline

Long non-coding RNAs play an important role in regulating photoperiod-and temperature-sensitive male sterility in rice

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Science China(Life Sciences) 2017年第4期60卷 443-444页

作者： Jingxin guo yao-Guang Liu State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources Key Laboratory of Plant Functtonal Genomicsand Biotechnology of Guangdong Provincial Higher Education Institutions College of Life Sciences South China Agricultural University Guangzhou 510642 China

Rice(Oryza sativa L.)is a major food crop for more than half of the world’s ***,increasing rice production is of great *** successful development of hybrid rice in the 1970s was an important achievement for increasing yield potential,since hybrid rice varieties produce higher yields than inbred varieties(Cheng et al.,2007).In plants,male sterility refers to the inability of producing dehiscent anthers and functional pollen(Chen and Liu,2014).

关键词： sterility inbred pollen alleles inability producing recessive fertility regulating sterile

Transition-layer Solutions of Quasilinear Elliptic Boundary Blow-up Problems and Dirichlet Problems

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Acta Mathematica Sinica,English Series 2011年第11期27卷 2177-2190页

作者： Zong Ming guo yao Yong YAN Department of Mathematics He＇nan Normal University Xinxiang 453007 P. R. China

We study profiles of positive solutions for quasilinear elliptic boundary blow-up problems and Dirichlet problems with the same equation：where ω 〉 0, a（x） is a continuous function satisfying 0 〈 a（x）〈 1 for x ∈Ω, Ω is a bounded smooth domain in R^N. We will see that the profile of a minimal positive boundary blow-up solution of the equation shares some similarities to the profile of a positive minimizer solution of the equation with homogeneous Dirichlet boundary condition.

关键词： Quasilinear elliptic boundary blow-up problems quasilinear elliptic Dirichlet problems transition-layer solutions minimizer solutions

Quadrilaterals, extremal quasiconformal extensions and Hamilton sequences

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Applied Mathematics(A Journal of Chinese Universities) 2010年第2期25卷 217-226页

作者： CHEN Zhi-guo ZHENG Xue-liang yao guo-wu Department of Mathematics Zhejiang University Hangzhou 310028 China Department of Mathematics Taizhou College Linhai 317000 China Department of Mathematical Sciences Tsinghua University Beijing 100084 China

The relationship between Strebel boundary dilatation of a quasisymmetric function h of the unit circle and the dilatation indicated by the change in the modules of the quadrilaterals with vertices on the circle intrigues many mathematicians. It had been a conjecture for some time that the dilatations Ko（h） and K1（h） of h are equal before Anderson and Hinkkanen disproved this by constructing concrete counterexamples. The independent work of Wu and of Yang completely characterizes the condition for Ko（h） = K1 （h） when h has no substantial boundary point. In this paper, we give a necessary and sufficient condition to determine the equality for h admitting a substantial boundary point.

关键词： Extremal quasiconformal mapping quasisymmetric mapping Hamilton sequence substantial boundary point.

A novel posture alignment system for aircraft wing assembly

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2009年第11期10卷 1624-1630页

作者： Bin ZHANG Bao-guo yao Ying-lin KE College of Mechanical and Energy Engineering Zhejiang University Hangzhou 310027 China

A novel 6-degree of freedom (DOF) posture alignment system, based on 3-DOF positioners, is presented for the assembly of aircraft wings. Each positioner is connected with the wing through a rotational and adsorptive half-ball shaped end-effector, and the positioners together with the wing are considered as a 3-PPPS (P denotes a prismatic joint and S denotes a spherical joint) redundantly actuated parallel mechanism. The kinematic model of this system is established and a trajectory planning method is introduced. A complete analysis of inverse dynamics is carried out with the Newton-Euler algorithm, which is used to find the desired actuating torque in the design and path planning phase. Simulation analysis of the displacement and actuating torque of each joint of the positioners based on inverse kinematics and dynamics is conducted, and the results show that the system is feasible for the posture alignment of aircraft wings.

关键词： Aircraft wings Three-coordinate positioner Posture alignment Kinematics Dynamics

Synthesis and characterization of biodegradable thermoplastic elastomers derived from N.N-bis （2-carboxyethyl）-pyromellitimide, poly（butylene succinate） and polyethylene glycol

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Frontiers of Chemical Science and Engineering 2018年第3期12卷 457-466页

作者： Jiaojiao Shang guo yao Ronghui guo Wei Zheng Long Gu Jianwu Lan College of Light Industry and Textile and Food Engineering Sichuan University Chengdu 610065 China

Abstract Biodegradable poly（ether-imide-ester） elasto- mers were synthesized from succinic acid, 1,4-butanediol, polyethylene glycol 1000 and N＇,N-bis（2-carboxyethyl）- pyromellitimide which was derived from pyromellitic dianhydride and glycine. The chemical structures, crystal- linities, thermal stabilities, mechanical properties, hydro- philicities and biodegradabilities of these elastomers were investigated. The hard segments of the linear aliphatic poly （ether-ester） exhibited monoclinic chain packing. Increas- ing the amount of aromatic bisimide moieties in the poly （ether-ester） reduced the crystallinity of the material and improved the thermal stability and tensile strength of the elastomers. In addition, introducing a suitable amount of aromatic bisimide moieties into the poly（ether-ester） backbones endowed the elastomers with improved biode- gradability but too many aromatic bisimide groups reduced the biodegradability of the elastomers.

关键词： thermoplastic elastomers biodegradability thermo-stability mechanical property aromatic bisimide moiety

Effect of Preparation Methods of Bi_(2)O_(3) Nanoparticles on their Photocatalytic Activity

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Chemical Research in Chinese Universities 2004年第6期20卷 717-721页

作者： DING Peng DU yao-guo XU Zi-li Department of Environment Science College of Environment and ResourcesJilin UniversityChangchun 130023P.R.China Department of Chemistry Changchun Normal CollegeChangchun 130032P.R.China

Bi 2O 3 nanoparticles were prepared by means of ammonia precipitation, polyol mediated methods and microemulsion chemical method. The structure and properties of the as-prepared nanoparticles, having been submitted to a heat-treatment test at 750 ℃, were characterized by means of XRD, BET, XPS and UV-Vis absorption techniques. The photocatalytic oxidation reactions of benzene, toluene and xylene were used as the model reaction to measure the photocatalytic activity of Bi 2O 3 nanoparticles, respectively. The results show that the crystallite size of Bi 2O 3 prepared with different methods and calcined at 750 ℃ were 50.6, 38.5 and 31.5 nm, respectively. The photocatalytic activity of Bi 2O 3 nanoparticles prepared with the microemulsion chemical method was higher than that of the particles prepared with the polyol mediated method; and that of the particles prepared with the micromulsion chemical method was the highest among the three. The degradation rates of the three pollutants xylene, toluene and benzene decreased in sequence.

关键词： Bi_(2)O_(3) Preparation method Characterization Photocatalytic activity

Acquisition performance of B1I abounding with 5G signals

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Journal of Systems Engineering and Electronics 2022年第3期33卷 563-574页

作者： SHANG Peng WANG Xue ZOU Decai CHU Ziyue guo yao National Time Service Center Chinese Academy of SciencesXi’an 710600China University of Chinese Academy of Sciences Beijing 101408China Key Laboratory of Precision Navigation and Timing Technology Chinese Academy of SciencesXi’an 710600China Institute of Information Sensing Xidian UniversityXi’an 710600China School of Astronomy and Space Science University of Chinese Academy of SciencesBeijing 100049China

The widespread 5G base stations can be potential jammers for the vulnerable BeiDou B1I receivers due to its low ***,a novel analytical model is derived for the 5G signal to evaluate its impact on acquisition performance under three decision *** good agreement between the Monte Carlo method(MCM)through software defined receiver(SDR)and the derived expressions validates the effectiveness of the proposed *** can be found that the receivers exhibit varied responses for different 5G waveforms and decision *** receiver also shows the least endurances for some kind of 5G waveforms,however,this kind of adverse effect can be cancelled by a reduced interference signal ratio(ISR),an increased integration time or a larger accumulation times.

关键词： 5G new radio(NR) coexistence evaluation acquisition performance software defined receiver(SDR)