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Design and Cryogenic Performance of a Hexapod Platform for a Large Ground-based Wide Field Survey Telescope

Research in Astronomy and Astrophysics 2024年第1期24卷 178-187页

作者： Yang Yu Xue-Wen Wang Yu Zhang jia-lin sun Zhen-Bang Xu jian-Li Wang Changchun Institute of Optics Fine Mechanics and PhysicsChinese Academy of SciencesChangchun 130033China Chinese Academy of Sciences Key Laboratory of On-orbit Manufacturing and Integration for Space Optics System Changchun 130033China University of Chinese Academy of Sciences Beijing 100049China

The thermal gradient is an important factor that causes degradation to the image quality of telescopes. In order to ensure the accurate alignment of the primary focus unit and the primary mirror, the hexapod platform(as a corrector) is investigated in this paper. First, a ground-based telescope with 2.5 m aperture and 3.5 deg field of view is described. The telescope is under construction, and it is expected to be finished in 2023. Second, the hexapod platform with flexure hinges utilized to adjust the primary focus unit is proposed, which is applied as a ***, the inverse kinematics of the platform is established and an open-loop control system is built based on ***, the cryogenic performance test for the hexapod platform is performed. The experimental results show that the resolution and repeatability of the translation for the hexapod platform can be achieved at the micrometer *** resolution and repeatability of the rotation can be achieved at the arc-second level. Therefore, the cryogenic performance of the hexapod platform can meet the optical imaging requirements of the wide-field ground-based telescope. The kinematic analysis and cryogenic performance tests in the paper provide a technical reference for the precise alignment of the primary focus unit and the primary mirror, which can improve the imaging quality of the telescope.

关键词： methods:miscellaneous space vehicles:instruments telescopes miscellaneous

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Acatulides A-G,neuroprotective macrolides from Acaulium album H-JQSF

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Chinese Chemical Letters 2024年第3期35卷 379-383页

作者： Zhi-Wu Tong Ting-Ting Wang Pei Yang jia-lin sun Chen-Peng Zhang Salman Khan Xin-Cun Wang Rui-Hua jiao Hui-Ming Ge Wen-Ying Zhuang Gang Hu Ren Xiang Tan State Key Laboratory of Pharmaceutical Biotechnology Institute of Functional BiomoleculesNanjing UniversityNanjing 210023China State Key Laboratory Cultivation Base for TCM Quality and Efficacy Nanjing University of Chinese MedicineNanjing 210023China Insitute of Microbiology Chinese Academy of SciencesBeijing 100101China

Fungal symbionts co-evolve with hosts and microbial co-inhabitants to acquire an unpredictable potential for producing novel bioactive metabolites,but the knowledge about the topic remains patchy and *** we present the chemical characterization of acatulides A-G(1-7)as architecturally unprecedented macrolides from the solid-state culture of Acaulium album H-JQSF,an arthropod-associated *** acatulide structures were elucidated by spectroscopic analysis,modified Mosher's method and single-crystal X-ray *** plausible biosynthetic pathways for compounds 1-4 are ***,acatulides B-D(2-4)and G(7)were demonstrated to be neuroprotective against the 1-methyl-4-phenylpyridinium(MPP+)-induced damage to SH-SY5Y cells and nematode Caenorhabditis elegans(***).

关键词： Acaulium album Macrolides Acatulides A–G Mosher’s method Neuroprotective

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Novel Photodetectors Based on Double-Walled Carbon Nanotube Film/TiO2 Nanotube Array Heterodimensional Contacts

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Nano Research 2011年第9期4卷 901-907页

作者： Mingjie Yang jia-lin Zhu Wei Liu jia-lin sun Department of Physics and State Key Lab of Low-Dimensional Quantum Physics Tsinghua University Beijing 100084 China Laboratory of Advanced Materials Department of Material Science and Engineering Tsinghua University Beijing 100084 China

A new kind of photodetector based on a double-walled carbon nanotube （DWCNT） film and a TiO2 nanotube array with hetrodimensional non-ohmic contacts has been fabricated. Due to the dimensionality difference effect, the DWCNT film/TiO2 nanotube array photodetector exhibits a much higher photocurrent-to-dark current ratio and photoresponse relative to an Au film/TiO2 nanotube array device, even at small bias voltage. The photocurrent-to-dark current ratio reached four orders of magnitude and a high photoresponse of 2467 A/W was found upon irradiation at 340 nm. Furthermore, the photosensitive regions could be extended into the visible range. The photocurrent-to-dark current ratio reached approximately three orders of magnitude upon irradiation at 532 nm, where the photon energy is much lower than the band gap of TiO2.

关键词： Photodetectors double-wailed carbon nanotube (DWCNT) films TiO2 nanotube arrays heterodimensional contacts

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Fabrication of double-walled carbon nanotube film/TiO_2 nanotube array heterojunctions with length-dependent photoresponse for broad band photodetectors

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International Journal of Minerals,Metallurgy and Materials 2013年第3期20卷 307-312页

作者： Ming-jie Yang Wei Liu jia-lin sun Jin-quan Wei jia-lin Zhu Laboratory of Advanced Materials Department of Material Science and Engineering Tsinghua University State Key Laboratory of Low-Dimensional Quantum Physics Department of Physics Tsinghua University Key Laboratory for Advanced Materials Processing Technology of Education Ministry Department of Mechanical Engineering Tsinghua University

A novel photodetector based on double-walled carbon nanotube （DWCNT） film/TiO2 nanotube array （TNA） heterojunctions was fabricated, which exhibited high photoresponse in a broad spectral range. The photoresponse of the detector was dramatically dependent on the length of the TNAs. High photocurrent-to-dark current ratio with a value of 3360 was observed in the visible range by optimizing the lengths of the TNAs. The photosensitive regions could be extended into the near-infrared range. These results reveal that DWCNT film/TNA heterojunctions show potential applications for broad band photodetectors.

关键词： photodetectors titanium dioxide carbon nanotubes heterojunctions

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Novelty phase synthesis mechanism and morphology in resin-bonded Al–Al2O3–TiO2 composites at high temperatures under flowing N2

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International Journal of Minerals,Metallurgy and Materials 2019年第9期26卷 1177-1185页

作者： Yang sun Yong Li Li-xin Zhang Shi-ming Li Ming-wei Yan jia-lin sun School of Materials Science and Engineering University of Science and Technology BeijingBeijing 100083China Sinosteel Refractory Co. Ltd. Henan 471039China Beijing Cisri-nmt Environmental Science and Technology Co. Ltd. Beijing 100083China

An Al–AlN core–shell structure is beneficial to the performance of Al–Al2O3 composites. In this paper, the phase evolution and microstructure of Al–Al2O3–TiO2 composites at high temperatures in flowing N2 were investigated after the Al–AlN core–shell structure was created at 853 K for 8 h. The results show that TiO2 can convert Al into Al3Ti(~1685 K), which reduces the content of metal Al and rearranges the structure of the composite. Under N2 conditions, Al3Ti is further transformed into a novelty non-oxide phase, TiCN. The transformation process can be expressed as follows: Al3Ti reacts with C and other carbides(Al4C3 and Al4O4C) to form TiCx(x < 1). As the firing temperature increases, Al3Ti transforms into a liquid phase and produces Ti(g) and TiO(g). Finally, Ti(g) and TiO(g) are nitrided and solid-dissolved into the TiCx crystals to form a TiCN solid solution.

关键词： aluminum titanium oxide alloys titanium carbonitride

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Effects of metal binder on the microstructure and mechanical properties of Al2O3-based micro-nanocomposite ceramic tool material

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International Journal of Minerals,Metallurgy and Materials 2017年第7期24卷 826-832页

作者： Xiu-ying Ni Jun Zhao jia-lin sun Feng Gong Zuo-li Li Key Laboratory of High Efficiency and Clean Mechanical Manufacture of the Ministry of Education Shandong University Jinan 250061 China

The Al_2O_3-（W,Ti）C composites with Ni and Mo additions varying from 0vol% to 12vol% were prepared via hot pressing sintering under 30 MPa. The microstructure was investigated via X-ray diffraction（XRD） and scanning electron microscopy（SEM） equipped with energy dispersive spectrometry（EDS）. Mechanical properties such as flexural strength, fracture toughness, and Vickers hardness were also measured. Results show that the main phases A12O3 and（W,Ti）C were detected by XRD. Compound Mo Ni also existed in sintered nanocomposites. The fracture modes of the nanocomposites were both intergranular and transgranular fractures. The plastic deformation of metal particles and crack bridging were the main toughening mechanisms. The maximum flexural strength and fracture toughness were obtained for 9vol% and 12vol% additions of Ni and Mo, respectively. The hardness of the composites reduced gradually with increasing content of metals Ni and Mo.

关键词： ceramic matrix nanocomposite metal phase microstructure mechanical properties

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Reinforcing effect of graphene on the mechanical properties of Al2O3/TiC ceramics

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International Journal of Minerals,Metallurgy and Materials 2017年第12期24卷 1403-1411页

作者： Zuo-li Li Jun Zhao jia-lin sun Feng Gong Xiu-ying Ni Key Laboratory of High Efficiency and Clean Mechanical Manufacture of Ministry of Education School of Mechanical EngineeringShandong UniversityJinan 250061China

Multilayer graphene(MLG)-reinforced Al_2O_3/TiC ceramics were fabricated through hot pressing sintering, and the reinforcing effect of MLG on the microstructure and mechanical properties of the composites was investigated by experiment and simulation. The simulation of dynamic crack initiation and propagation was investigated based on the cohesive zone method. The results show that the composite added with 0.2 wt% MLG has excellent flexural strength and high fracture toughness. The major reinforcing mechanisms are the synergistic effect by strong and weak bonding interfaces, MLG pull-out, and grain refinement resulting from the addition of MLG. In addition, the aggravating of crack deflection, branching, blunting, and bridging have indispensable contribution to the improvement of the as-designed materials.

关键词： mechanical properties ceramics graphene simulation interface

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Shear-thickening behavior of Fe-ZSM5 zeolite slurry and its removal with alumina/boehmites

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International Journal of Minerals,Metallurgy and Materials 2018年第6期25卷 682-688页

作者： Xiao-guang Liu Yan Li Wen-dong Xue jia-lin sun Qian Tang Department of Inorganic Nonmetallic Materials School of Materials Science and Engineering University of Science and Technology Beijing Atmospheric Environment Department Chinese Academy for Environmental Planning

A cryogenic scanning electron microscopy（cryo-SEM） technique was used to explore the shear-thickening behavior of Fe-ZSM5 zeolite pastes and to discover its underlying mechanism. Bare Fe-ZSM5 zeolite samples were found to contain agglomerations, which may break the flow of the pastes and cause shear-thickening behaviors. However, the shear-thickening behaviors can be eliminated by the addition of halloysite and various boehmites because of improved particle packing. Furthermore, compared with pure Fe-ZSM5 zeolite samples and its composite samples with halloysite, the samples with boehmite（Pural SB or Disperal） additions exhibited network structures in their cryo-SEM images; these structures could facilitate the storage and release of flow water, smooth paste flow, and avoid shear-thickening. By contrast, another boehmite（Versal 250） formed agglomerations rather than network structures after being added to the Fe-ZSM5 zeolite paste and resulted in shear-thickening behavior. Consequently, the results suggest that these network structures play key roles in eliminating the shear-thickening behavior.

关键词： Fe-ZSM5 zeolite cryogenic scanning electron microscopy shear-t^ickening behavior zeta potential boel^nite

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Reaction behavior of trace oxygen during combustion of falling FeSi75 powder in a nitrogen flow

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International Journal of Minerals,Metallurgy and Materials 2016年第8期23卷 959-965页

作者： Bin Li Jun-hong Chen Peng jiang Ming-wei Yan jia-lin sun Yong Li School of Materials Science and Engineering University of Science and Technology Beijing

To explore the reaction behavior of trace oxygen during the flash combustion process of falling FeSi75 powder in a nitrogen flow, a flash-combustion-synthesized Fe-Si;N;sample was heat-treated to remove SiO;. The samples before and after the treatment were investigated by X-ray diffraction, scanning electron microscopy, and transmission electron microscopy, and the formation mechanism of SiO;was investigated. The results show that SiO;in the Fe-Si;N;is mainly located on the surface or around the Si;N;particles in dense areas, existing in both crystalline and amorphous states; when the FeSi75 particles, which are less than 0.074 mm in size, fell in up-flowing hot N;stream, trace oxygen in the N;stream did not significantly hinder the nitridation of FeSi75 particles as it was consumed by the surface oxidation of the generated Si;N;particles to form SiO;. At the reaction zone, the oxidation of Si;N;particles decreased the oxygen partial pressure in the N;stream and greatly reduced the opportunity for FeSi75 particles to be oxidized into SiO;; by virtue of the SiO;film developed on the surface, the Si;N;particles adhered to each other and formed dense areas in the material.

关键词： silicon nitride combustion synthesis oxygen atmosphere

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Comparative study of different membranes as separators for rechargeable lithium-ion batteries

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International Journal of Minerals,Metallurgy and Materials 2013年第6期20卷 598-603页

作者： Hong-yan Guan Fang Lian Yan Ren Yan Wen Xiao-rong Pan jia-lin sun School of Materials Science and Engineering University of Science and Technology Beijing

Membranes of polypropylene （PP）, PP coated with nano-A1203, PP electrospun with polyvinylidene fluoride- hexafluoropropylene （PVdF-HFP）, and trilayer laminates of polypropylene-polyethylene-polypropylene （PP/PE/PP） were comparatively studied. Their physical properties were characterized by means of thermal shrinkage test, liquid electrolyte uptake, and field emission scanning electron microscopy （FESEM）. Results show that, for the different membranes as PP, PP coated with nanowA1203, PP electrospun with PVdF-HFP, and PP/PE/PP, the thermal shrinkages are 14%, 6%, 12.6%, and 13.3%, while the liquid electrolyte uptakes are 110%, 150%, 217%, and 129%, respectively. In addition, the effects on the performance of lithium-ion batteries （LiFePO4 and linil/3Col/3Mn1/302 as the cathode material） were investigated by AC impedance and galvanostatic charge/discharge test. It is found that PP coated with A1203 and PP electrospun with PVdF-HFP can effectively increase the wettability between the cathode material and liquid electrolyte, and therefore reduce the charge transfer resistance, which improves the capacity retention and battery performance.

关键词： lithium-ion batteries membranes separators thermal stability electrochemical properties

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