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Image Field Deformation of LAMOST due to Differential Atmospheric Refraction

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Chinese Journal of Astronomy and Astrophysics 2006年第4期6卷 495-502页

作者： Jin-Ling Li Bo Zhang Yong Yu zhao-xiang qi Ming zhao Shanghai Astronomical Observatory Chinese Academy of Sciences Shanghai 200030

A vectorial expression of the image field deformation of LAMOST due to the differential atmospheric refraction is presented. The calculated results are compared with those from previous analyses based on the traditional spherical trigonometric formulas. It is demonstrated that different tangential displacements of star images during the observation tracking given by various authors are simply due to different reference points adopted. It is pointed out that the observational celestial pole is the center of the apparent diurnal motion, that, by referring to the observational celestial pole, the effect of the differential refraction on the image field of LAMOST during the 1.5-hour tracking period is approximately equivalent to a constant rotation of - 13.65″ for all declination belts. It is therefore unnecessary to design a particular tracking velocity for each observation, and this will be obviously advantageous to the observation implementation. If the maximum tracking error of the fibers is 0.2″, then the fibers are required to be able to re-position during observational tracking for sky regions south of declination ＋20° and north of declination ＋60°.

关键词： telescopes -- atmospheric effects -- methods: analytical-- methods: statistical-- astrometry

Synergistic effects of multiscale TiC and dual-phase structure on tensile properties of particle-reinforced steel

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Journal of Iron and Steel Research International 2024年第5期31卷 1232-1245页

作者： Ye Jia xiang-tao Deng qi Wang Cheng-ru Li Hao Wu zhao-dong Wang State Key Laboratory of Rolling and Automation Northeastern UniversityShenyang110819LiaoningChina

The conventional melting methods were used to obtain in situ TiC particle-reinforced dual-phase steel,followed by hot rolling and heat treatment *** aim was to investigate the effect of TiC particles on the fracture behavior of dual-phase steel at different annealing temperatures,by analyzing the microstructure and tensile behavior of the multiscale TiC particle-reinforced dual-phase *** results showed that TiC particles precipitated in the as-cast microstructure of dual-phase steel were distributed along the grain *** hot rolling,the grain boundary-like morphology of the micron-sized TiC particles was disrupted,and the particles became more refined and evenly distributed in the *** tensile tests revealed that the strength of the TiC particle-reinforced dual-phase steel increased with increasing martensite content,while the elongation *** results were similar to those of conventional *** addition of 1 vol.%multiscale TiC particles improved the strength of the dual-phase steel but did not affect elongation of the *** and holes were primarily concentrated around the TiC particles rather than at the interface of martensite and *** main causes of crack sprouting were TiC particle interface cracking and TiC particle internal ***,the study demonstrated the potential of multiscale TiC particle-reinforced dual-phase steel as a strong and tough *** refined distribution of TiC particles in the matrix improved the strength of the material without compromising its *** results also highlighted the importance of careful selection of reinforcement particles to avoid detrimental effects on the fracture behavior of the material.

关键词： TiC particle Dual-phase structure TiC-reinforced dual-phase steel Tension Fracture behavior

A new telescope with three fields of view to measure the orientation parameters of the Moon and terrestrial planets

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维普期刊数据库

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Research in Astronomy and Astrophysics 2021年第2期21卷 121-132页

作者： Li-Zao Sun Cheng-Li Huang Yong Yu zhao-xiang qi Zheng-Hong Tang Ming zhao De-Hua Yang Tong Wu Shanghai Astronomical Observatory Chinese Academy of SciencesShanghai 200030China CAS Key Laboratory of Planetary Sciences Shanghai Astronomical ObservatoryChinese Academy of SciencesShanghai 200030China School of Astronomy and Space Science University of Chinese Academy of SciencesBeijing 100049China College of Automation Engineering Nanjing University of Aeronautics and AstronauticsNanjing 211106China Key Laboratory of Space Photoelectric Detection and Sensing of Ministry of Industry and Information Technology College of AstronauticsNanjing University of Aeronautics and AstronauticsNanjing 211106China

For lots of scientific questions about lunar physics deep inside the Moon,in-situ observation on lunar physical libration is one of the most potential *** this paper,we propose a brand new optical telescope functioned with simultaneously observing multiple(here there are three)fields of view(FOVs)for in-situ observation of lunar physical *** telescope can be placed at any place with any attitude on the Moon and do not require manned install,control or *** passively,continuously and simultaneously observe stars in three FOVs along with rotation of the *** is to be measured and studied from celestial motion of the directions of three FOVs from image *** concept and design of this telescope are firstly introduced in this *** principle and feasibility of the method of insitu observation are also *** simulation,precision of the determined lunar physical libration is expected to be several milliarcsecs,about two orders of magnitude better than the current precision of libration by lunar laser ranging *** data with milliarcsec precision level can play a valuable role in the study of the physics and dynamics of the interior of the *** telescope can also be applied to observe the rotation of other terrestrial planets like Mars.

关键词： astrometry-telescopes-methods observational-reference systems

The spectrum and stability of travelling pulses in a coupled FitzHugh-Nagumo equation

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Science China Mathematics 2024年第5期67卷 975-1010页

作者： qi qiao xiang Zhang School of Mathematical Sciences Shanghai Jiao Tong UniversityShanghai 200240China Key Laboratory of Scientific and Engineering Computing(Ministry of Education) and Shanghai Frontier Science Center of Modern Analysis(CMA-Shanghai)Shanghai Jiao Tong UniversityShanghai 200240China

For a coupled slow-fast FitzHugh-Nagumo(FHN)equation derived from a reaction-diffusionmechanics(RDM)model,Holzer et al.(2013)studied the existence and stability of the travelling pulse,which consists of two fast orbit arcs and two slow ones,where one fast segment passes the unique fold point with algebraic decreasing and two slow ones follow normally hyperbolic critical curve *** and Zhang(2021)obtained the existence of the travelling pulse,whose two fast orbit arcs both exponentially decrease,and one of the slow orbit arcs could be normally hyperbolic or not at the ***,we characterize both the nonlinear and spectral stability of this travelling pulse.

关键词： coupled FitzHugh-Nagumo equation singular perturbation travelling pulse spectrum nonlinear stability spectral stability

Research progress of heterogeneous structure magnesium alloys:A review

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Journal of Magnesium and Alloys 2024年第6期12卷 2147-2181页

作者： xiang Chen Junlei Zhang Min Wang Weizhang Wang Di zhao Haiming Huang qi zhao Xiaofei Xu Hongxia Zhang Guangsheng Huang Hubei Longzhong Laboratory Wuhan University of Technology Xiangyang Demonstration ZoneXiangyang 441000China College of Materials Science and Engineering Hubei University of Automotive TechnologyShiyan 442002China College of Materials Science and Engineering Kunming University of Science and TechnologyKunming 650093China Hubei Key Laboratory of Energy Storage and Power Battery(Hubei University of Automotive Technology) Shiyan 442002China College of Materials Science and Engineering Chongqing UniversityChongqing 400044China School of Mechanical Engineering Suzhou University of Science and TechnologySuzhou 215009China

In recent years,a new class of metallic materials featuring heterogeneous structures has *** materials consist of distinct soft and hard domains with significant differences in mechanical properties,allowing them to maintain high strength while offering superior ***(Mg)alloys,renowned for their low density,high specific strength,exceptional vibration damping,and electromagnetic shielding properties,exhibit tremendous potential as lightweight and functional *** their advantageous properties,high-strength Mg alloys often suffer from limited ***,the emergence of heterogeneous materials provides a fresh perspective for the development of Mg alloys with both high strength and *** article provided a fundamental overview of heterostructured materials and systematically reviewed the recent research progress in the design of Mg alloys with strength-ductility balance based on heterostructure *** review encompassed various aspects,including preparation methods,formation mechanisms of diverse heterostructures,and mechanical properties,both within domestic and international *** this basis,the article discussed the challenges encountered in the design and fabrication of heterostructured Mg alloys,as well as the urgent issues that require attention and resolution in the future.

关键词： Mg alloys Heterogeneous structure Processing techniques Strength and ductility Hetero-deformation induced stress Strain gradient

Continuous Orbit Equivalence of Semigroup Actions

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Acta Mathematica Sinica,English Series 2024年第6期40卷 1581-1598页

作者： xiang qi qiANG Cheng Jun HOU School of Mathematical Science Yangzhou UniversityYangzhou 225002P.R.China

We introduce notions of continuous orbit equivalence and its one-sided version for countable left Ore semigroup actions on compact spaces by surjective local homeomorphisms,and characterize them in terms of the corresponding transformation groupoids and their operator *** particular,we show that two essentially free semigroup actions on totally disconnected compact spaces are continuously orbit equivalent if and only if there is a canonical abelian subalgebra preserving C^(∗)-isomorphism between the associated transformation groupoid C^(∗)-*** also give some examples of orbit equivalence,consider the special case of semigroup actions by homeomorphisms and relate continuous orbit equivalence of semigroup actions to that of the associated group actions.

关键词： Semigroup action continuous one-sided orbit equivalence continuous orbit equivalence groupoid C^(∗)-algebras

Understanding the spatial interaction of ultrasounds based on three-dimensional dual-frequency ultrasonic field numerical simulation

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China Foundry 2024年第1期21卷 29-43页

作者： zhao-yang Yin qi-chi Le Yan-chao Jiang Da-zhi zhao qi-yu Liao qi Zou Key Lab of Electromagnetic Processing of Materials Ministry of EducationNortheastern UniversityShenyang 110819China School of Materials Science and Engineering Northeastern UniversityShenyang 110819China

A transient 3D model was established to investigate the effect of spatial interaction of ultrasounds on the dual-frequency ultrasonic field in magnesium alloy *** effects of insertion depth and tip shape of the ultrasonic rods,input pressures and their ratio on the acoustic field distribution were discussed in ***,the spacing,angle,and insertion depth of two ultrasonic rods significantly affect the interaction between distinct *** a result,various acoustic pressure distributions and cavitation regions are *** spherical rods mitigate the longitudinal and transversal attenuation of acoustic pressure and expand the cavitation volume by 53.7%and 31.7%,respectively,compared to the plate and conical *** the input pressure will enlarge the cavitation region but has no effect on the acoustic pressure distribution *** acoustic pressure ratio significantly affects the pressure distribution and the cavitation region,and the best cavitation effect is obtained at the ratio of 2:1(P15:P20).

关键词： dual-frequency ultrasonic numerical model acoustic pressure spatial interaction magnesium alloy

Regio-and Stereoselective Polymerization of Bio-based Ocimene by Rare-Earth Metal Catalysts

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Chinese Journal of Polymer Science 2024年第2期42卷 223-229,I0008页

作者： qi-Yuan Wang Li-Peng Sang Zhen Zhang Yang Jiang Hui Tian Xia zhao xiang Guo Shi-Hui Li State Key Laboratory of Polymer Physics and Chemistry Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun130022China School of Applied Chemistry and Engineering University of Science and Technology of ChinaHefei230026China Science and Technology on Aerospace Chemical Power Laboratory Hubei Institute of Aerospace ChemotechonologyXiangyang441003China Shanxi Coal Chemical Industry Technology Research Institute Xi’an710000China Hubei Institute of Aerospace Chemotechonology Xiangyang441003China

Coordination polymerization of renewable β-ocimene has been investigated using asymmetric diiminophosphinate lutetium complex1, β-diketiminate yttrium complex 2, bis(phosphino)carbazolide yttrium complex 3, half-sandwich benzyl fluorenyl scandium complex 4 and pyridyl-methylene-fluorenyl rare-metal complexes 5a–5c. Complexes 1, 4 and 5a–5c show trans-1,2-regioselectivities and high activities, of which 5c exhibits excellent isoselectivity(mmmm>99%). Conversely, complexes 2 and 3 promote β-ocimene polymerization to produce isotactic cis-1,4-polyocimenes(cis-1,4>99%, mm>95%). Diblock copolymers cis-1,4-PIP-block-cis-1,4-POc and cis-1,4-PBD-block-cis-1,4-POc are obtained in one-pot reactions of β-ocimene with isoprene and butadiene using complex 3. Epoxidation and hydroxylation of polyocimene afford functionalized polyolefins with enhanced T_(g)(from-20 ℃ to 79 ℃ and 74 ℃) and hydrophilicity.

关键词： Biobased monomer Terpenes Ocimene Rare-earths Polymerization Regio/stereoselectivity Elastomer

Anomalous{1012}tensile twinning and subsequent detwinning in a friction stir processed carbon fiber-reinforced Mg composite

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Journal of Magnesium and Alloys 2024年第4期12卷 1511-1517页

作者： Wei zhao Zhihao Jiang xiang Wu Yujing Liu Haokun Yang Jun Wang qi Liu Xiaochun Liu Institute of Metals College of Materials Science and EngineeringChangsha University of Science&TechnologyChangsha 410114China Department of Mechanical Engineering City University of Hong KongHong KongChina Smart manufacturing division Hong Kong Productivity CouncilHong Kong SAR 999077China Institute for Frontier Materials Deakin UniversityGeelongVIC 3216Australia Department of Industrial and Systems Engineering The Hong Kong Polytechnic UniversityHong KongChina

*** text Owing to their low density and high specific strength,magnesium alloys and magnesium-based composites have great potential as structure metal materials in applications where lightweight matters[1–4].Deformation twins[5],especially the{1012}tension twins(also called tensile or extension twins)with a low critical resolved shear stress(CRSS)[6],are commonly observed in Mg *** can provide the much-needed deformation along the c-axis in their hcp structure resulting from the very few easily activated slip systems in this crystal structure[7].The tensile twinning activation usually follows the macroscopic Schmid factor law[2],i.e.,the twin variant with the highest Schmid factor occurs,and it only appears when its Schmid factor is positive.

关键词： friction deformation magnesium