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Nanostructured Catalyst for Fischer-Tropsch Synthesis

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Chinese Journal of Chemistry 2018年第9期36卷 798-808页

作者： wa Gao Qingshan Zhu Ding ma College of Chemistry and Molecular engineering and College of engineering Peking University Beijing 100871 China Fritz-Haber-Institut der max-Planck-Gesellschaft Faradayweg 4-6 D-14195 Berlin Germany

Fischer-Tropsch synthesis （FTS） is a heterogeneous catalytic process for the production of fuels or chemicals from synthesis gas （CO ＋ H2）, which can be derived from nonpetroleum feedstocks such as natural gas, coal, or biomass. Co, Ru, Fe and Ni are all active in FTS, but only cheaper Fe and Co based catalysts are used in industry because the price of Ru is relatively high. However, the industrial Fe- and Co-based FTS catalysts normally work at a relatively high temperature range of 493--623 K in order to get a reasonable space time yield. Moreover, the product selectivity of FTS is governed by the law of polymerization, i.e., a so-called Anderson-Schulz-FIory distribution holds, which restricts its industrial application. In this account, we highlight some of our progress toward the design/fabrication of nanostructured Fe, Co and Ru catalysts to improve FTS activity at the low temperature and to change the product selectivity and confine the product distribution into a certain range.

关键词： catalyst Fischer-Tropsch synthesis nanostructure

Vector meson's spin alignments in high energy reactions

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Science China(Physics,Mechanics & Astronomy) 2025年第1期Mechanics & Astronomy) .卷 5-20页

作者： Jin-Hui Chen Zuo-Tang Liang Yu-Gang ma Xin-Li Sheng Qun wang Key Laboratory of Nuclear Physics and Ion-beam Application (Moe) Institute of Modern PhysicsFudan University Institute of Frontier and Interdisciplinary Science Key Laboratory of Particle Physics and Particle Irradiation (MOE)Shandong University INFN-Firenze Department of Modern Physics University of Science and Technology of China School of Mechanics and Physics Anhui University of Science and Technology

The global spin alignment of vector mesons has been observed by the STAR collaboration at the Relativistic Heavy Ion Collider （RHIC） at Brookhaven National Laboratory （BNL）.It provides a unique opportunity to probe the correlation between the polarized quark and antiquark in the strongly coupled quark-gluon plasma （sQGP） produced in relativistic heavy ion collisions,opening a new window to explore the properties of s *** addition,spin alignments of vector mesons have also been observed in other high-energy particle collisions such as e+e-annihilations at high energies where hadron production is dominated by quark fragmentation *** results obtained are quite different from those obtained in heavy ion collisions where quark coalescence/combination mechanism dominates suggesting strong dependence on hadronization *** comprehensive studies in different hadronization processes are *** this article,we present a brief review of theoretical and experimental advances in the study of vector meson’s spin alignments in a variety of high-energy particle collisions,with emphasis on hadronization mechanisms.

关键词： vector meson spin alignment global polarization relativistic heavy ion collisions fragmentation

efficient and Stable Photoassisted Lithium-Ion Battery enabled by Photocathode with Synergistically Boosted Carriers Dynamics

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NANO-MICRO LeTTeRS 2025年第1期17卷 1-15页

作者： ma, Zelin wang, Shiyao ma, Zhuangzhuang Li, Juan Zhao, Luomeng Li, Zhihuan wang, Shiyuan Shuang, Yazhou wang, Jiulong wang, Fang Xia, Weiwei Jian, Jie He, Yibo wang, Junjie Guo, Pengfei wang, Hongqiang Northwestern Polytech Univ Ctr Nano Energy Mat State Key Lab Solidificat Proc Sch Mat Sci & Engn Xian 710072 Peoples R China NPU Shaanxi Joint Lab Graphene Xian 710072 Peoples R China Northwestern Polytech Univ Sch Mat Sci State Key Lab Solidificat Proc Xian 710072 Peoples R China Northwestern Polytech Univ Engn Dept Xian 710072 Peoples R China Northwestern Polytech Univ Ctr Adv Lubricat & Seal Mat Sch Mat Sci & Engn State Key Lab Solidificat Proc Xian 710072 Peoples R China Northwestern Polytech Univ Shenzhen Res & Dev Inst Shenzhen 518063 Peoples R China Shaanxi Normal Univ Key Lab Appl Surface & Colloid Chem Shaanxi Engn Lab Adv Energy Technol Shaanxi Key Lab Adv Energy DevicesSch Mat Sci & E Xian 710119 Peoples R China

efficient and stable photocathodes with versatility are of significance in photoassisted lithium-ion batteries (PLIBs), while there is always a request on fast carrier transport in electrochemical active photocathodes. Present work proposes a general approach of creating bulk heterojunction to boost the carrier mobility of photocathodes by simply laser assisted embedding of plasmonic nanocrystals. When employed in PLIBs, it was found effective for synchronously enhanced photocharge separation and transport in light charging process. Additionally, experimental photon spectroscopy, finite difference time domain method simulation and theoretical analyses demonstrate that the improved carrier dynamics are driven by the plasmonic-induced hot electron injection from metal to TiO2, as well as the enhanced conductivity in TiO2 matrix due to the formation of oxygen vacancies after Schottky contact. Benefiting from these merits, several benchmark values in performance of TiO2-based photocathode applied in PLIBs are set, including the capacity of 276 mah g(-1 ) at 0.2 A g(-1 )under illumination, photoconversion efficiency of 1.276% at 3 A g(-1 ), less capacity and Columbic efficiency loss even through 200 cycles. These results exemplify the potential of the bulk heterojunction strategy in developing highly efficient and stable photoassisted energy storage systems.

关键词： Photoassisted lithium-ion batteries Bulk heterojunction Carrier dynamics TiO2 nanofiber Plasmonic metal nanocrystals

Vision-based positioning system

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The Journal of China Universities of Posts and Telecommunications 2016年第5期23卷 88-96页

作者： Song Meina ou Zhonghong e Haihong Song Junde Zhao Xuejun School of Computer Science Beijing University of Posts and Telecommunications

Conventional outdoor navigation systems are usually based on orbital satellites, e.g., global positioning system （GPS） and global navigation satellite system （GLONASS）. The latest advances from wearable, e.g., Baidueye and Google Glass, have enabled new approaches to leverage information from the surrounding environment. For example, they enable the change from passively receiving information to actively requesting information. Thus, such changes might inspire brand new application scenarios that were not possible before. In this work, we propose a vision-based navigation system based on wearable like Baidu eye. We discuss the associated challenges and propose potential solutions for each of them. The system utilizes crowd sensing to collect and build a traffic signpost database for positioning reference. Then it leverages context information, such as cell identification （Cell ID）, signal strength, and altitude combined with traffic sign detection and recognition to enable real-time positioning. A hybrid cloud architecture is proposed to enhance the capability of sensing devices （SD） to realize the proposed vision.

关键词： vision-based positioning system wearable machine vision

Realization of the global yield mechanism of RC frame structures by redesigning the columns using column tree method

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Science China(Technological Sciences) 2015年第10期58卷 1627-1637页

作者： BAI JiuLin ou JinPing School of Civil engineering Harbin Institute of Technology Key Lab of Structures Dynamic Behavior and Control (Harbin Institute of Technology) Ministry of Education

Global failure mechanism, i.e., the strong-column weak-beam mechanism, can provide higher total energy dissipation capacity with less ductility demand on components than other failure modes, and results in a more uniform story drift distribution and higher resistance to earthquake loads at the system level. However, the current code-based elastic design method cannot guarantee the global failure mechanism of frame structures under severe earthquakes. In this paper, a simple, but practical design procedure is proposed to ensure the global failure mechanism of reinforced concrete(RC) frame structures by redesigning the columns using the column tree method(CTM). CTM considers the yield limit state of all beams and column bases. The code-based design is firstly carried out to determine the section information of all beams and base columns. Then, the internal force demands applied on the column tree can be derived. Lastly, the column moments, shear forces and axial forces are determined according to the free-body diagram of CTM to finish the column redesign. Two RC frame structures with 6 and 12 stories are illustrated to verify the design procedure. The analytical results demonstrate the proposed approach can realize the global failure mechanism.

关键词： global failure mechanism column tree method (CTM) reinforced concrete frame structures failure mode plastic hinges

Hyperbolicity of elliptic Lagrangian orbits in the planar three body problem

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Science China mathematics 2014年第7期57卷 1539-1544页

作者： ou YuWei Department of mathematics Shandong University

The linear stability of Lagrangian elliptic equilateral triangle homographic solutions in the classical planar three body problem depends on the mass parameter β = 27（m1m2 ＋ m2m3 ＋ m3m1）/（m1 ＋ m2 ＋ m3）2∈ [0,9] and the eccentricity e ∈ [0,1）.In this paper we use maslov-type index to study the stability of these solutions and prove that the elliptic Lagrangian solutions is hyperbolic for β ＆gt; 8 with any eccentricity.

关键词： planar three-body problem Lagrangian solution hyperbolicity maslov-type index

effect of 5-Aza-2’-deoxycytidine on immune-associated proteins in exosomes from hepatoma

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World Journal of Gastroenterology 2010年第19期16卷 2371-2377页

作者： Gao-wa Sanren Department of Histology and embryology Inner Mongolia Medical College Hohhot 010010 Inner Mon-golia Autonomous Region China

AIM: To study the effect of 5-Aza-2’-deoxycytidine (5-Aza-CdR) on heat shock protein 70 (HSP70), human leucocyte antigen-Ⅰ (HLA-Ⅰ) and NY-eSO-1 proteins in exosomes produced by hepatoma cells, HepG2 and Hep3B. MeTHODS: exosomes derived from HepG2 and Hep3B cells treated with or without 5-aza-CdR were isolated and purified by ultrafiltration centrifugation and sucrose gradient ultracentrifugation. The number of exosomes was counted under electron microscope. Concentration of proteins in exosomes was measured by bicinchoninic acid protein assay. expression of HSP70, HLA-Ⅰ and NY-eSO-1 proteins in exosomes was detected by Western blotting and immunoelectron microscopy. mRNA expression of p53 gene was detected by reverse transcription polymerase chain ***: The mRNA expression of p53 gene was increased in both hepatoma cell lines after treatment with 5-Aza-CdR. The number of exosomes and the concentration of total proteins in exosomes were increased signifi cantly after treatment with 5-aza-CdR (P er treatment with 5-Aza-CdR, immunoelectron microscopy and Western blotting showed that the HSP70, HLA-Ⅰ and NY-eSO-1 proteins were increased in exosomes produced by both hepatoma cell lines. CONCLUSION: 5-aza-CdR, an inhibitor of DNA methyltransferase, can increase exosomes produced by hepatoma cells and immune-associated protein component of exosomes, which may be mediated by p53 gene upregulation and 5-Aza-CdR demethylation.

关键词： 5-Aza-2’-deoxycytidine exosome Immu-nomolecule Hepatoma cell

Study on polarization properties of graphene coated D-shaped fiber

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Chinese Physics B 2018年第10期27卷 346-351页

作者： Xuejing Liu Luwen Yang Jingyun ma Caili Li wa Jin Weihong Bi School of Instrumentation Science and Opto-electronics engineering Beihang UniversityBeijing 100191China School of Information Science and engineering Key Laboratory for Special Fiber and Fiber Sensor of Hebei ProvinceYanshan UniversityQinhuangdao 066004China Key Laboratory for Special Fiber and Fiber Sensor of Hebei Province School of Information Science and EngineeringQinhuangdao 066004China

The optical properties of graphene coated D-shaped single mode fiber and photonic crystal fiber are numerically analyzed. enhancement of the graphene-light interaction is found in graphene coated D-shaped photonic crystal fiber,which introduces a tunable polarization of the D-shaped fiber by changing the chemical potential of the coated *** optimal polarizer model is demonstrated with the extinction ratio of 66.26 dB/mm and the insertion loss of 9.4 dB/*** modulator extinction ratios of the Te mode and TM mode are 11.5 dB and 5 dB, respectively, with a device length of100 μm. This paper provides a theoretical reference for the optical property research of the graphene fiber.

关键词： photonic crystal fiber graphene polarization chemical potential

A comparative analysis of optimization and generalization properties of two-layer neural network and random feature models under gradient descent dynamics

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Science China mathematics 2020年第7期63卷 1235-1258页

作者： Weinan e Chao ma Lei Wu Department of mathematics Princeton UniversityPrincetonNJ 08544USA The Program in Applied and Computational mathematics Princeton UniversityNJ 08544USA Beijing Institute of Big Data Research Beijing 100871China

A fairly comprehensive analysis is presented for the gradient descent dynamics for training two-layer neural network models in the situation when the parameters in both layers are *** initialization schemes as well as general regimes for the network width and training data size are *** the overparametrized regime,it is shown that gradient descent dynamics can achieve zero training loss exponentially fast regardless of the quality of the *** addition,it is proved that throughout the training process the functions represented by the neural network model are uniformly close to those of a kernel *** general values of the network width and training data size,sharp estimates of the generalization error are established for target functions in the appropriate reproducing kernel Hilbert space.

关键词： two-layer neural network random feature model Gram matrix generalization error